Designing low-power, cloud-connected IoT devices with PSoC® 6 MCU’s and WICED® Wi-Fi/Bluetooth

Summary

In this lesson we will move the subscriber app functionality into the main GameBle project (now called GameBleAws).  In order to do this, you need to turn the subscriber into a thread, and fix it so that messages that are sent to the PADDLE topic get turned into messages that can be sent to the paddleQueue.

To implement this lesson I will follow these steps:

1. Create a New Project starting from L6GameBle
2. Copy over subscriber.c and wifi_config_dct.h
3. Update the Makefile
4. Create subscriber.h
5. Update main.c
6. Update subscriber.c
7. Test

Create a New Project

Copy and paste the L6GameBle project into a new project called L8GameBleAws using Copy/Paste

Create a new Make target for the GameBleAws project

Copy subscriber.c & wifi_config_dct.h

Use copy/paste to make a copy of the subscriber application and paste it into the GameBleAws project.  Once done your folder should look like this:

Update the Makefile

NAME := App_WStudio_L8GameBleAws
$(NAME)_SOURCES := main.c \
CapSenseThread.c \
GameThread.c \
cy_tft_display.c \
GoBleThread.c \
GoBle_db.c \
wiced_bt_cfg.c \
subscriber.c
$(NAME)_COMPONENTS := graphics/ugui \
libraries/drivers/bluetooth/low_energy \
protocols/AWS
WIFI_CONFIG_DCT_H := wifi_config_dct.h
$(NAME)_RESOURCES  := apps/aws/iot/rootca.cer \
apps/aws/iot/subscriber/client.cer \
apps/aws/iot/subscriber/privkey.cer
# To support Low memory platforms, disabling components which are not required
GLOBAL_DEFINES += WICED_CONFIG_DISABLE_SSL_SERVER \
WICED_CONFIG_DISABLE_DTLS \
WICED_CONFIG_DISABLE_ENTERPRISE_SECURITY \
WICED_CONFIG_DISABLE_DES \
WICED_CONFIG_DISABLE_ADVANCED_SECURITY_CURVES

Create subscriber.h

In order for the main.c to know about the awsThread (which is the former application_start of subscriber.c) you should create a file called subscriber.h.  Then you should define the awsThread function to match the wiced_thread_t function prototype (just a function that takes a wiced_thread_arg and returns void).

#pragma once
extern void awsThread( wiced_thread_arg_t arg );

Update main.c

To integrate the awsThread thread into your main project you need to add the “subscriber.h” to the includes:

#include "GameThread.h"
#include "GoBleThread.h"
#include "CapSenseThread.h"
#include "subscriber.h"
#include "wiced.h"

Add a new variable to hold the awsThreadHandle.

wiced_thread_t awsThreadHandle;

Finally you should launch the AWS thread by creating it with wiced_rtos_create_thread.

void application_start( )
{
wiced_init( );
wiced_rtos_init_queue(&paddleQueue,"paddleQueue",sizeof(game_msg_t),10);
wiced_rtos_create_thread(&blinkThreadHandle,7,"Blink Thread",pdlBlinkThread,500,0);
wiced_rtos_create_thread(&capsenseThreadHandle,7,"CapSense Thread",capSenseThread,1024,0);
wiced_rtos_create_thread(&gameThreadHandle,7,"game Thread",gameThread,4096,0);
GoBleThread_start();
wiced_rtos_create_thread(&awsThreadHandle,7,"AWS Thread",awsThread,4096,0);
}

Update subscriber.c

In order for subscriber.c to be useful you need to fix the includes, send the messages from the PADDLE topic to the game thread, and turn application_start into a thread.  Start by fixing the includes (just like we did in the BLE Example in Lesson 6)

#include "SystemGlobal.h"
#include "GameThread.h"

When you get a message to the PADDLE topic, you should parse it, then send a message to the game thread to move the paddle.  You do this exactly the same way as you did in the BLE project.  Notice that I protect the game thread by making sure it send a value less than 100.

        case WICED_AWS_EVENT_PAYLOAD_RECEIVED:
{
uint32_t val;
WPRINT_APP_INFO( ("[Application/AWS] Payload Received[ Topic: %.*s ]:\n", (int)data->message.topic_length, data->message.topic ) );
if(strncmp(WICED_TOPIC,(const char *)data->message.topic,strlen(WICED_TOPIC)) == 0 && data->message.data_length < 4)
{
sscanf((const char *)data->message.data,"%d",(int *)&val);
if(val>100)
val = 100;
WPRINT_APP_INFO(("Val = %d\n",(int)val));
game_msg_t msg;
msg.evt = MSG_POSITION;
msg.val = val;
wiced_rtos_push_to_queue(&paddleQueue,&msg,0);
}
}
break;

Test

I don’t really have a good program (like the GoBle) to test moving the paddle live.  But you can see that when the game is over, you can still move the paddle using AWS console.  In the screen shot below you can see that I moved the paddle to position 0.  And you can see that the BLE started at the same time as AWS.  Score.

Designing low-power, cloud-connected IoT devices with PSoC® 6 MCU’s and WICED® Wi-Fi/Bluetooth

Summary

In this lesson I am going to update one of the predefined application which we deliver as part of WICED Studio which knows how to connect to the AWS IoT Cloud to work on my network.  This will demonstrate WiFi and MQTT.  I will also fix the application so that it knows about a new MQTT Topic called “PADDLE” which will be used to send messages to move the game paddle.

To implement this project I will:

1. Copy the subscriber from demo/aws/iot/pub_sub/subscriber
2. Setup a “thing” on AWS and download the certificates
3. Update the certificates in the WICED installation
4. Update the project with my AWS configuration
5. Test
6. Update the project to be compatible with the Game
7. Test

Copy Subscriber & Fix the Makefile

The first thing that I will do is copy/paste the subscriber application which can be found at demo/aws/iot/pub_sub/subscriber into my folder.  I will also rename the project to L7subscriber. Once that is done it should look like this:

Then you need to edit the Makefile to update the name of the project.

NAME := App_WStudio_L7subscriber

Go to Amazon.com and Create a “thing”

In order to connect to the AWS cloud you need to create a “thing”.  Go to the AWS console and click “Create”

We are just going to create one thing.  So, click “Create a single thing”

Give it a name, in this case Mouser.

AWS has device level security which is implemented with RSA certificates for each device.  So,  you need to let AWS create a certificate for you.

Once that is done download the device certificate and the two keys.  You need to 100% make sure you do this now, because you wont get another chance. I’m also going to activate the certificate once I have the certificate and keys.

Now attach a policy to your thing.  I already have the “ww101_policy” setup.

The policy looks like this.  Basically, things are wide open.

Update the Certificates

The last thing that you need is the most recent AWS certificate.  WICED expects that you use the RSA2048 bit key.

Now that you have the four security documents., you need to integrate them into your WICED installation.  To do this, change directories to ~/Documents/WICED-Studio-6.2/43xxx_Wi-Fi/resources/apps/aws/iot  Then copy the files, and then make symbolic links.  If you are not on a Mac or Linux then just copy the files and rename them appropriately.

Update the Project

AWS creates a virtual machine and runs an MQTT server on that machine.  You can find out the DNS name of that machine on the settings screen.  Here you can see my endpoint.  You will need to configure the WICED project to talk to your server.

You need to change the actual endpoint of your MQTT server in the AWS cloud on line 119

static wiced_aws_endpoint_info_t my_subscriber_aws_iot_endpoint = {
.transport           = WICED_AWS_TRANSPORT_MQTT_NATIVE,
.uri                 = "amk6m51qrxr2u-ats.iot.us-east-1.amazonaws.com",
.peer_common_name    = NULL,
.ip_addr             = {0},
.port                = WICED_AWS_IOT_DEFAULT_MQTT_PORT,
.root_ca_certificate = NULL,
.root_ca_length      = 0,
};

In the file wifi_config_dct.h you will need to change the CLIENT_AP_SSID and CLIENT_AP_PASSPHRASE for your network

/* This is the default AP the device will connect to (as a client)*/
#define CLIENT_AP_SSID       "WW101WPA"
#define CLIENT_AP_PASSPHRASE "yourpassword"
#define CLIENT_AP_BSS_TYPE   WICED_BSS_TYPE_INFRASTRUCTURE
#define CLIENT_AP_SECURITY   WICED_SECURITY_WPA2_MIXED_PSK
#define CLIENT_AP_CHANNEL    1
#define CLIENT_AP_BAND       WICED_802_11_BAND_2_4GHZ

Test

In order to test the project you will need to create a make target and program your development kit.

Once that is done you can go to the Amazon.com test console and send MQTT messages to the correct topic.

Here you can see the project attached to my network.  And successfully received the LIGHT ON message.

Update the Project for the Game

We know that the game doesn’t care about the LIGHT topic so, let’s change it to PADDLE.

#define WICED_TOPIC                                 "PADDLE"

And let’s assume that messages to the paddle topic are ASCII numbers <100.  So, we can parse the message and print it out.  Notice that I used sscanf to parse the message and we all know that is super dangerous.

        case WICED_AWS_EVENT_PAYLOAD_RECEIVED:
{
char buff[10];
uint32_t val;
WPRINT_APP_INFO( ("[Application/AWS] Payload Received[ Topic: %.*s ]:\n", (int)data->message.topic_length, data->message.topic ) );
if(strncmp(WICED_TOPIC,data->message.topic,strlen(WICED_TOPIC)) == 0 && data->message.data_length < 4)
{
sscanf(data->message.data,"%d",&val);
WPRINT_APP_INFO(("Val = %d\n",val));
}
}
break;

Test

After making those updates let’s program the whole shooting match again.  Then test by sending some messages to the PADDLE topic.

It’s good.  Things are working.

Designing low-power, cloud-connected IoT devices with PSoC® 6 MCU’s and WICED® Wi-Fi/Bluetooth

Summary

At this point we have a working BLE Remote Control and a working Game.  In this lesson I’ll merge the two projects together so that the GoBle remote control will be able to control the game paddle.  It will do this by creating messages (just like the CapSense messages) and sending them to the Game thread via the paddleQueue.  And it will send “Button0” messages when “Button A” is pressed.

To implement this lesson I will follow these steps:

1. Copy everything into a new project
2. Modify the Makefile
3. Modify main.c
4. Create a new make target
5. Test it all to make sure things are still working
6. Modify GoBleThread.c
7. Program and Test

Copy L4Game into a new project L6GameBle

Use “copy” and “paste” to create a new project, when you paste give it the name “L6GameBle” (there is an error in the screenshot)

Copy the files GoBle_db.c/h, GoBleThread.c/h, and wiced_bt_cfg.c from the GoBle project into your new GameBle project.  After that is done your project should look like this:

Modify the Makefile

1. Change the name of the App to “App_WStudio_L6GameBle”
2. Add the new source files
3. Add the BLE Library “libraries/drivers/bluetooth/low_energy”

NAME := App_WStudio_L6GameBle
$(NAME)_SOURCES := main.c \
CapSenseThread.c \
GameThread.c \
cy_tft_display.c \
GoBleThread.c \
GoBle_db.c \
wiced_bt_cfg.c
$(NAME)_COMPONENTS := graphics/ugui \
libraries/drivers/bluetooth/low_energy

Modify main.c

Add the include for the GeBleThread.

#include "GameThread.h"
#include "GoBleThread.h"
#include "CapSenseThread.h"
#include "wiced.h"

In the application_start function add a call GoBleThread_start() to get the GoBle thread going

void application_start( )
{
wiced_init( );
wiced_rtos_init_queue(&paddleQueue,"paddleQueue",sizeof(game_msg_t),10);
wiced_rtos_create_thread(&blinkThreadHandle,7,"Blink Thread",pdlBlinkThread,500,0);
wiced_rtos_create_thread(&capSenseThreadHandle,7,"CapSense Thread",capSenseThread,1024,0);
wiced_rtos_create_thread(&gameThreadHandle,7,"game Thread",gameThread,4096,0);
GoBleThread_start();
}

Create a new make target

Test it all to make sure things are still working

Run the make target and make sure that the game still plays and that you can get remote control messages.

Modify GoBleThread.c

Add the includes for the GameThread (to get access to the game message structure) and SystemGlobal (to get access to the queue)

#include "GameThread.h"
#include "SystemGlobal.h"

I don’t need (or want) the button/slider printout information.  So I will delete the old button code from goble_event_handler. (delete this stuff)

            WPRINT_APP_INFO(("# Buttons = %d ButtonMask=%02X Slider x=%02X Slider Y=%02X Raw=",(int)numButtons,(unsigned int)buttonMask,(unsigned int)sliderX,(unsigned int)sliderY));
for(int i=0;i<p_attr_req->data.write_req.val_len;i++)
{
WPRINT_APP_INFO(("%02X ",p_attr_req->data.write_req.p_val[i]));
}
WPRINT_APP_INFO(("\n"));

Now, update the code to send the slider and button information to the GameThread (via the paddleQueue).  You may have noticed that the slider on GoBle gives you 0->0xFF and the direction is the inverse from the game we setup.  So, I will scale the value to 100 and invert it so that the controller moves the paddle the right way on line 143.  The message format is exactly the same as what we setup for the CapSense.  This means the CapSense slider works at the same time as the GoBle controller.

   case GATT_ATTRIBUTE_REQUEST_EVT:
p_attr_req = &p_event_data->attribute_request;
if( p_attr_req->request_type == GATTS_REQ_TYPE_WRITE  && p_attr_req->data.handle == HDLC_GOBLE_SERIALPORTID_VALUE)
{
uint32_t numButtons = p_attr_req->data.write_req.p_val[3];
uint32_t sliderY = p_attr_req->data.write_req.p_val[5+numButtons];
uint32_t sliderX = p_attr_req->data.write_req.p_val[6+numButtons];
uint32_t buttonMask = 0x00;
for(int i=0;i<numButtons;i++)
{
buttonMask |= (1<<p_attr_req->data.write_req.p_val[5+i]);
}
game_msg_t msg;
msg.evt = MSG_POSITION;
msg.val = 100 - (100*sliderY/255);
wiced_rtos_push_to_queue(&paddleQueue,&msg,0);
if(buttonMask & 0x10)
{
msg.evt = MSG_BUTTON0;
msg.val = 1;
wiced_result_t result=wiced_rtos_push_to_queue(&paddleQueue,&msg,0);
}
status = WICED_BT_GATT_SUCCESS;
}
break;

Program and Test

Designing low-power, cloud-connected IoT devices with PSoC® 6 MCU’s and WICED® Wi-Fi/Bluetooth

Summary

In this lesson I’ll finish the video game thread by adding the graphics etc. to play the game.  In addition I’ll fix up the CapSense thread so that it is connected to the game via an RTOS queue.

There are three main things going on in this game.

1. A state machine for the game screen (Splash, Start, Running, Over)
2. A 20ms timer that updates the screen while the game is running (moves the Paddle and the Ball)
3. A GUI queue where the rest of the system – CapSense,  Bluetooth and WiFi – can send Button and Paddle messages.

To implement this project I will:

1. Setup the project and makefile by copying L3CapSenseTft
2. Update gamethread.h to define the GUI queue messages
3. Fix main.c to create the queue
4. Create SystemGlobal.h to give the rest of the files access to the gui queue
5. Updating the CapSenseThread to send GUI messages
6. Update the includes in GameThread.c
7. Add some #define macros to define game parameters
8. Add a State Machine for the game & define some paddle movement methods
9. Make forward declarations for the thread functions
10. Create some variables to maintain game state
11. Add display functions for the score and the speed
12. Add functions to start and end the game
13. Add helper functions to calculate the top and bottom of the paddle
14. Add a function to update and draw the paddle
15. Add a function to update and draw the ball
16. Add a function for the game timer to call
17. Update the main game thread

Setup the project and makefile by copying L3CapSenseTft

Use copy/paste to copy the L3CapSenseTft project to a new folder name L4Game.   Change the name of the makefile to be L4Game.mk.

Edit the makefile and change the name of the application.

NAME := App_WStudio_L4Game
$(NAME)_SOURCES := main.c \
CapSenseThread.c \
GameThread.c \
cy_tft_display.c
$(NAME)_COMPONENTS := graphics/ugui

Create a make target for this project

Update GameThread.h to Define the GUI Messages

All of the threads in the system (CapSense, Bluetooth, and WiFi) will control the paddle and the button by sending messages to an RTOS queue.  In gameThread.h we will add a definition of that message.  The message is just a structure with two values – which GUI element and what value to send.

#pragma once
#include "wiced.h"
typedef enum {
MSG_POSITION,
MSG_BUTTON0,
MSG_BUTTON1,
} game_evt_t;
typedef struct {
game_evt_t evt;
uint32_t val;
} game_msg_t;
void gameThread(wiced_thread_arg_t arg);

Fix main.c to Create the Queue

I typically believe that the RTOS primitives should be owned by the main.c.  To do this edit main.c and fix the includes.

#include "GameThread.h"
#include "wiced.h"
#include "CapSenseThread.h"
#include "SystemGlobal.h"

Then define the queue variable “paddleQueue” which I should have names “guiQueue” but it is way to late to fix it now — oh well.

/******************************************************
*               Variable Definitions
******************************************************/
wiced_thread_t blinkThreadHandle;
wiced_thread_t capSenseThreadHandle;
wiced_thread_t gameThreadHandle;
wiced_queue_t paddleQueue;

Create the queue

void application_start( )
{
wiced_init( );
wiced_rtos_init_queue(&paddleQueue,"paddleQueue",sizeof(game_msg_t),10);
wiced_rtos_create_thread(&blinkThreadHandle,7,"Blink Thread",pdlBlinkThread,500,0);
wiced_rtos_create_thread(&capSenseThreadHandle,7,"CapSense Thread",capSenseThread,1024,0);
wiced_rtos_create_thread(&gameThreadHandle,7,"game Thread",gameThread,4096,0);
}

Create SystemGlobal.h

Each of the threads in the system need to have access to the paddleQueue.  In order to do that create a file called SystemGlobal.h and extern the variable to give them that access.

#pragma once
extern wiced_queue_t paddleQueue;

Updating the CapSenseThread to send GUI messages

Remember that when we setup the CapSenseThread originally, it just printed out the values.  Let’s fix it so send messages.  So, edit CapSenseThread.c.

1. Add a message variable (line 8)
2. Fix the button0 and button 1 to make and send RTOS messages (lines 20/21 and 26/27)
3. Fix the slider to send the position (lines 33-35)

#include "wiced.h"
#include "GameThread.h"
#include "SystemGlobal.h"
void capSenseThread(wiced_thread_arg_t arg)
{
game_msg_t msg;
CapSense_Start();
CapSense_ScanAllWidgets();
while(1)
{
if(!CapSense_IsBusy())
{
CapSense_ProcessAllWidgets();
if(CapSense_IsWidgetActive(CapSense_BUTTON0_WDGT_ID))
{
msg.evt = MSG_BUTTON0;
wiced_rtos_push_to_queue(&paddleQueue,&msg,0);
}
if(CapSense_IsWidgetActive(CapSense_BUTTON1_WDGT_ID))
{
msg.evt = MSG_BUTTON1;
wiced_rtos_push_to_queue(&paddleQueue,&msg,0);
}
uint32_t val = CapSense_GetCentroidPos(CapSense_LINEARSLIDER0_WDGT_ID);
if(val < 0xFFFF)
{
msg.evt = MSG_POSITION;
msg.val = val;
wiced_rtos_push_to_queue(&paddleQueue,&msg,0);
}
CapSense_ScanAllWidgets();
}
wiced_rtos_delay_milliseconds(25); // Poll every 25ms (actual scan time ~8ms)
}
}

Update the includes in GameThread.c

Now let’s fix GameThread.c.  Start by editing the includes to add a new file called “SystemGlobal.h” which contains the global variable for the GUI queue.

#include "GameThread.h"
#include "cy_tft_display.h"
#include "SystemGlobal.h"
#include "ugui.h"

Add some #define macros in GameThread.c

There are a number of constants which I use in the game.  In this section I use #define macros to define them.

#define UPDATE_SCREEN_TIME (20) // Update the screen every 20ms
#define SPEED (2)
#define SCREEN_X (320)
#define SCREEN_Y (240)
#define TOP_FIELD (21)
#define PD_WIDTH (10)
#define PD_LEN (70)
#define DOTS (3)
#define PADDLE0_COLOR (C_BLUE)
#define BALL_COLOR (C_GREEN)
#define BALL_SIZE (10)

Add a State Machine for the Game & Define Paddle Movement

Open up GameThread.c – all of the game control functions will go there.

There will be four screens in the game.  A splash screen to display Cypress and Mouser, a Ready Player 1 Screen, the actual game screen and a game over screen.

In addition the paddle can move a little bit at a time (increment) or jump directly to the position (absolute)

// States of the game
typedef enum {
GS_SPLASH,
GS_START,
GS_RUNNING,
GS_OVER
} game_state_t;
// Methods to move the paddle
typedef enum {
PADDLE_INCREMENT,
PADDLE_ABSOLUTE
} paddle_update_t;

Fix the gameState statemachine

In the splash screen I need to set the state machine to GS_SPLASH

static void displaySplashScreen()
{
gameState = GS_SPLASH;
UG_FontSelect( &FONT_22X36 );
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/5,22,36,"Cypress");
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/5*2,22,36,"Mouser");
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/5*3,22,36,"PSoC 6");
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/5*4,22,36,"WICED 4343");
wiced_rtos_delay_milliseconds(2000);
}

In the start screen I need to set the state machine to GS_START

// Display the Start Screen
static void  displayStartScreen()
{
gameState = GS_START;
UG_FillScreen( C_BLACK );
UG_FontSelect( &FONT_22X36 );
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/2 -2 - 18 ,22,36,"Ready");
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/2 + 2 + 18 ,22,36,"Player 1");
displayStartButton();
}

Make Forward Declarations for Functions

You should define the functions in advance of using them

/******************************************************
*               Static Function Declarations
******************************************************/
static void UG_PutStringCenter(uint32_t x, uint32_t y, uint32_t fontx, uint32_t fonty,char *string);
static void displaySplashScreen();
static void displayStartButton();
static void  displayStartScreen();
static void displayScore();
static void displaySpeed();
static void endGame();
static inline uint32_t calcPaddleTop();
static inline uint32_t calcPaddleBottom();
static void updatePaddle(paddle_update_t type);
static void updateBall();
static void updateScreen(void *arg);

Create some variables to maintain game state

The updateScreenTimer is used while the game is running to call the updateScreen every 20ms.  The rest of the variables are self explanatory.

/******************************************************
*               Variable Definitions
******************************************************/
static UG_GUI   gui;
static wiced_timer_t updateScreenTimer;
static uint32_t gameScore;
static game_state_t gameState;
// position of the paddle
static uint32_t paddle0_desire_pos=0;
static uint32_t paddle0_cur_pos=0;
// Position, direction and speed of the ball
static uint32_t ballx,bally;
static int32_t ballXdir, ballYdir;
static uint32_t ballSpeed;

Add Display Functions for the Score & Speed

These two functions print the speed and score at the top of the screen.

// This function displays the score
static void displayScore()
{
char buff[10];
sprintf(buff,"%2X",(unsigned int)gameScore);
UG_FontSelect(&FONT_12X20);
UG_PutString( 75, 0, buff);
}
// This function displays the speed
static void displaySpeed()
{
char buff[10];
sprintf(buff,"%2X",(unsigned int)ballSpeed-1);
UG_FontSelect(&FONT_12X20);
UG_PutString( 275, 0, buff);
}

Add Function to Start the Game

When the game needs to start you:

1. Reset the score
2. Set the paddle position
3. Move the ball to the middle of the paddle
4. Set the ball to move to the right and down
5. Clear the screen, display score and speed
6. Start the game running

// This function initializes everything and starts a new game
static void startGame()
{
gameScore = 0;
paddle0_desire_pos = 50; // start the game with the paddle moving
paddle0_cur_pos = 0;
ballx = PD_WIDTH ;                   // start the ball on the paddle on the right of the screen
bally  = calcPaddleTop() + PD_LEN/2; // start the ball in the middle of the paddle
ballSpeed = SPEED;
ballXdir = ballSpeed;
ballYdir = ballSpeed;
UG_FillScreen( C_BLACK );  // clear screen
UG_FontSelect(&FONT_12X20);
UG_PutString( 0, 0,  "Score:");
displayScore();
UG_PutString(200,0,"Speed:");
displaySpeed();
UG_DrawLine(0,20,SCREEN_X,20,C_RED); // red line under text to represent top of play screen
gameState = GS_RUNNING;
wiced_rtos_start_timer(&updateScreenTimer); // Timer to update screen
}

Add Function to End the Game

When the game is over you should:

1. Move the game state to over
2. Stop the timer
3. Display game over
4. Display press button 0 to start

// Stop the game
static void endGame()
{
gameState = GS_OVER;
wiced_rtos_stop_timer(&updateScreenTimer);
UG_FontSelect( &FONT_22X36 );
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/2,22,36,"Game Over");
displayStartButton();
}

Add Helper Functions to Calculate Paddle Top & Bottom

There are two places where you need to know the position of the Paddle.  Specifically:

1. To draw the paddle
2. To figure out if the ball hit the paddle or not.

These two functions calculate the pixel position of the top and bottom of the paddle based on it current position

// Figure out the y position of the top of the paddle
static inline uint32_t calcPaddleTop()
{
return (paddle0_cur_pos)*DOTS+TOP_FIELD;
}
// Figure out the y position of the bottom of the paddle
static inline uint32_t calcPaddleBottom()
{
return (paddle0_cur_pos)*DOTS+PD_LEN+TOP_FIELD;
}

Add a Function to Update & Draw the Paddle

While the game is running you need the paddle to move.  There are two methods:

1. Absolute just moves the current position immediately to the desired position.
2. Incremental, which moves the paddle a little bit towards the desired position.

// Move the paddle either to : PADDLE_INCREMENT the next location or PADDLE_ABSOLUTE - final location
static void updatePaddle(paddle_update_t type)
{
// If the paddle is where it is supposed to be then just return
if(paddle0_cur_pos == paddle0_desire_pos)
return;
// erase the current paddle
UG_FillFrame(0,calcPaddleTop(),PD_WIDTH,calcPaddleBottom(),C_BLACK);
switch (type)
{
case PADDLE_INCREMENT:
if(paddle0_cur_pos < paddle0_desire_pos)
paddle0_cur_pos += SPEED;
else
paddle0_cur_pos -= SPEED;
// If the paddle is within one move of the final spot, put it there
if(abs((int)paddle0_cur_pos-(int)paddle0_desire_pos) < SPEED)
paddle0_cur_pos = paddle0_desire_pos;
break;
case PADDLE_ABSOLUTE:
paddle0_cur_pos = paddle0_desire_pos;
break;
}
// draw the paddle
UG_FillFrame(0,calcPaddleTop(),PD_WIDTH,calcPaddleBottom(),PADDLE0_COLOR);
}

Add a function to update and draw the ball

You need a function to:

1. Move the ball
2. Figure out if it hit the right/left/top/bottom of the screen and do the right thing.

When the ball hits one of those surfaces it needs to change direction to either plus or minus.

Every time it hits the paddle the score should increase and possibly speed up.

If it misses the paddle the game is over.

// Move the ball to the next location
static void updateBall()
{
static const uint32_t BallFudgeFactor=3;
UG_DrawCircle(ballx,bally,BALL_SIZE,C_BLACK);
ballx += ballXdir;
bally += ballYdir;
// Check to see if the ball hit the far right side
if(ballx > SCREEN_X - BALL_SIZE)
{
ballx = SCREEN_X - BALL_SIZE;
ballXdir = -ballSpeed;
}
// check to see if the ball hit the far left side... or the paddle
if(ballx < (BALL_SIZE + PD_WIDTH + BallFudgeFactor))
{
// See if the ball missed the paddle
if(bally + BALL_SIZE < calcPaddleTop() || bally - BALL_SIZE > calcPaddleBottom())
{
endGame();
//WPRINT_APP_INFO(("Missed Paddle\r\n"));
}
gameScore = gameScore + 1;
displayScore();
if(gameScore % 3 == 0) // Speed up every three hits
{
ballSpeed +=1;
displaySpeed();
}
ballx = BALL_SIZE + PD_WIDTH + BallFudgeFactor;
ballXdir = +ballSpeed;
}
// Check to see if the ball hit the top or bottom
if(bally > SCREEN_Y - BALL_SIZE) // bottom
{
bally = SCREEN_Y - BALL_SIZE;
ballYdir = -ballSpeed;
}
if(bally < TOP_FIELD+BALL_SIZE) // top
{
bally = BALL_SIZE+TOP_FIELD;
ballYdir = +ballSpeed;
}
UG_DrawCircle(ballx,bally,BALL_SIZE,BALL_COLOR);
}

Create a Function for the Game Timer

An RTOS timer runs every 20ms.  That timer needs a function to move the paddle and move the ball.

// This function is called every UPADTE_SCREEN_TIME milliseconds by the updateScreenTimer
static void updateScreen(void *arg)
{
updatePaddle(PADDLE_INCREMENT);
updateBall();
}

Update the Main Game Thread

The main game thread needs to get messages out of the queue and then do the right thing based on the game state.

// Main game thread
void gameThread(wiced_thread_arg_t arg)
{
game_msg_t msg;
Cy_TFT_Init();                                             // Init the TFT
UG_Init( &gui, Cy_TFT_displayDriver, SCREEN_X, SCREEN_Y ); // Connect the driver
UG_FillScreen( C_BLACK );   // Clear the screen
UG_SetBackcolor( C_BLACK );
UG_SetForecolor( C_WHITE );
wiced_rtos_init_timer(&updateScreenTimer,UPDATE_SCREEN_TIME,updateScreen,0);
displaySplashScreen();
displayStartScreen();
while(1)
{
wiced_rtos_pop_from_queue(&paddleQueue,&msg,WICED_WAIT_FOREVER);
switch(msg.evt)
{
case MSG_POSITION:
if(gameState == GS_RUNNING)
paddle0_desire_pos = msg.val/2;
if(gameState == GS_OVER)
{
paddle0_desire_pos = msg.val/2;
updatePaddle(PADDLE_ABSOLUTE);
}
break;
case MSG_BUTTON0:
if(gameState == GS_OVER || gameState == GS_START)
startGame();
break;
case MSG_BUTTON1:
break;
}
}
}

Program and Test

Now that it is all done… program and test it.

GameThread.c

Here is the whole thread is here so you can copy/paste it into your file.

#include "GameThread.h"
#include "cy_tft_display.h"
#include "SystemGlobal.h"
#include "ugui.h"
/******************************************************
*                      Macros
******************************************************/
#define UPDATE_SCREEN_TIME (20) // Update the screen every 20ms
#define SPEED (2)
#define SCREEN_X (320)
#define SCREEN_Y (240)
#define TOP_FIELD (21)
#define PD_WIDTH (10)
#define PD_LEN (70)
#define DOTS (3)
#define PADDLE0_COLOR (C_BLUE)
#define BALL_COLOR (C_GREEN)
#define BALL_SIZE (10)
/******************************************************
*                    Constants
******************************************************/
/******************************************************
*                   Enumerations
******************************************************/
/******************************************************
*                 Type Definitions
******************************************************/
// States of the game
typedef enum {
GS_SPLASH,
GS_START,
GS_RUNNING,
GS_OVER
} game_state_t;
// Methods to move the paddle
typedef enum {
PADDLE_INCREMENT,
PADDLE_ABSOLUTE
} paddle_update_t;
/******************************************************
*                    Structures
******************************************************/
/******************************************************
*               Static Function Declarations
******************************************************/
static void UG_PutStringCenter(uint32_t x, uint32_t y, uint32_t fontx, uint32_t fonty,char *string);
static void displaySplashScreen();
static void displayStartButton();
static void  displayStartScreen();
static void displayScore();
static void displaySpeed();
static void endGame();
static inline uint32_t calcPaddleTop();
static inline uint32_t calcPaddleBottom();
static void updatePaddle(paddle_update_t type);
static void updateBall();
static void updateScreen(void *arg);
/******************************************************
*               Variable Definitions
******************************************************/
static UG_GUI   gui;
static wiced_timer_t updateScreenTimer;
static uint32_t gameScore;
static game_state_t gameState;
// position of the paddle
static uint32_t paddle0_desire_pos=0;
static uint32_t paddle0_cur_pos=0;
// Position, direction and speed of the ball
static uint32_t ballx,bally;
static int32_t ballXdir, ballYdir;
static uint32_t ballSpeed;
/******************************************************
*               Functions
******************************************************/
// ARH Function to put text in the center of a point (UG_PutString does upper left)
static void UG_PutStringCenter(uint32_t x, uint32_t y, uint32_t fontx, uint32_t fonty,char *string)
{
y = y - fonty/2;
x = x - (strlen(string)/2)*fontx;
if(strlen(string)%2)
x = x - fontx/2;
UG_PutString(x,y,string);
}
// Display the splash screen
static void displaySplashScreen()
{
gameState = GS_SPLASH;
UG_FontSelect( &FONT_22X36 );
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/5,22,36,"Cypress");
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/5*2,22,36,"Mouser");
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/5*3,22,36,"PSoC 6");
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/5*4,22,36,"WICED 4343");
wiced_rtos_delay_milliseconds(2000);
}
// This function displays the start button message
static void displayStartButton()
{
UG_FontSelect(&FONT_12X20);
UG_PutStringCenter(SCREEN_X/2 , SCREEN_Y - 30 ,12,22,  "Press B0 To Start");
}
// Display the Start Screen
static void  displayStartScreen()
{
gameState = GS_START;
UG_FillScreen( C_BLACK );
UG_FontSelect( &FONT_22X36 );
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/2 -2 - 18 ,22,36,"Ready");
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/2 + 2 + 18 ,22,36,"Player 1");
displayStartButton();
}
// This function displays the score
static void displayScore()
{
char buff[10];
sprintf(buff,"%2X",(unsigned int)gameScore);
UG_FontSelect(&FONT_12X20);
UG_PutString( 75, 0, buff);
}
// This function displays the speed
static void displaySpeed()
{
char buff[10];
sprintf(buff,"%2X",(unsigned int)ballSpeed-1);
UG_FontSelect(&FONT_12X20);
UG_PutString( 275, 0, buff);
}
// This function initializes everything and starts a new game
static void startGame()
{
gameScore = 0;
paddle0_desire_pos = 50; // start the game with the paddle moving
paddle0_cur_pos = 0;
ballx = PD_WIDTH ;                   // start the ball on the paddle on the right of the screen
bally  = calcPaddleTop() + PD_LEN/2; // start the ball in the middle of the paddle
ballSpeed = SPEED;
ballXdir = ballSpeed;
ballYdir = ballSpeed;
UG_FillScreen( C_BLACK );  // clear screen
UG_FontSelect(&FONT_12X20);
UG_PutString( 0, 0,  "Score:");
displayScore();
UG_PutString(200,0,"Speed:");
displaySpeed();
UG_DrawLine(0,20,SCREEN_X,20,C_RED); // red line under text to represent top of play screen
gameState = GS_RUNNING;
wiced_rtos_start_timer(&updateScreenTimer); // Timer to update screen
}
// Stop the game
static void endGame()
{
gameState = GS_OVER;
wiced_rtos_stop_timer(&updateScreenTimer);
UG_FontSelect( &FONT_22X36 );
UG_PutStringCenter(SCREEN_X/2,SCREEN_Y/2,22,36,"Game Over");
displayStartButton();
}
// Figure out the y position of the top of the paddle
static inline uint32_t calcPaddleTop()
{
return (paddle0_cur_pos)*DOTS+TOP_FIELD;
}
// Figure out the y position of the bottom of the paddle
static inline uint32_t calcPaddleBottom()
{
return (paddle0_cur_pos)*DOTS+PD_LEN+TOP_FIELD;
}
// Move the paddle either to : PADDLE_INCREMENT the next location or PADDLE_ABSOLUTE - final location
static void updatePaddle(paddle_update_t type)
{
// If the paddle is where it is supposed to be then just return
if(paddle0_cur_pos == paddle0_desire_pos)
return;
// erase the current paddle
UG_FillFrame(0,calcPaddleTop(),PD_WIDTH,calcPaddleBottom(),C_BLACK);
switch (type)
{
case PADDLE_INCREMENT:
if(paddle0_cur_pos < paddle0_desire_pos)
paddle0_cur_pos += SPEED;
else
paddle0_cur_pos -= SPEED;
// If the paddle is within one move of the final spot, put it there
if(abs((int)paddle0_cur_pos-(int)paddle0_desire_pos) < SPEED)
paddle0_cur_pos = paddle0_desire_pos;
break;
case PADDLE_ABSOLUTE:
paddle0_cur_pos = paddle0_desire_pos;
break;
}
// draw the paddle
UG_FillFrame(0,calcPaddleTop(),PD_WIDTH,calcPaddleBottom(),PADDLE0_COLOR);
}
// Move the ball to the next location
static void updateBall()
{
static const uint32_t BallFudgeFactor=3;
UG_DrawCircle(ballx,bally,BALL_SIZE,C_BLACK);
ballx += ballXdir;
bally += ballYdir;
// Check to see if the ball hit the far right side
if(ballx > SCREEN_X - BALL_SIZE)
{
ballx = SCREEN_X - BALL_SIZE;
ballXdir = -ballSpeed;
}
// check to see if the ball hit the far left side... or the paddle
if(ballx < (BALL_SIZE + PD_WIDTH + BallFudgeFactor))
{
// See if the ball missed the paddle
if(bally + BALL_SIZE < calcPaddleTop() || bally - BALL_SIZE > calcPaddleBottom())
{
endGame();
//WPRINT_APP_INFO(("Missed Paddle\r\n"));
}
gameScore = gameScore + 1;
displayScore();
if(gameScore % 3 == 0) // Speed up every three hits
{
ballSpeed +=1;
displaySpeed();
}
ballx = BALL_SIZE + PD_WIDTH + BallFudgeFactor;
ballXdir = +ballSpeed;
}
// Check to see if the ball hit the top or bottom
if(bally > SCREEN_Y - BALL_SIZE) // bottom
{
bally = SCREEN_Y - BALL_SIZE;
ballYdir = -ballSpeed;
}
if(bally < TOP_FIELD+BALL_SIZE) // top
{
bally = BALL_SIZE+TOP_FIELD;
ballYdir = +ballSpeed;
}
UG_DrawCircle(ballx,bally,BALL_SIZE,BALL_COLOR);
}
// This function is called every UPADTE_SCREEN_TIME milliseconds by the updateScreenTimer
static void updateScreen(void *arg)
{
updatePaddle(PADDLE_INCREMENT);
updateBall();
}
// Main game thread
void gameThread(wiced_thread_arg_t arg)
{
game_msg_t msg;
Cy_TFT_Init();                                             // Init the TFT
UG_Init( &gui, Cy_TFT_displayDriver, SCREEN_X, SCREEN_Y ); // Connect the driver
UG_FillScreen( C_BLACK );   // Clear the screen
UG_SetBackcolor( C_BLACK );
UG_SetForecolor( C_WHITE );
wiced_rtos_init_timer(&updateScreenTimer,UPDATE_SCREEN_TIME,updateScreen,0);
displaySplashScreen();
displayStartScreen();
while(1)
{
wiced_rtos_pop_from_queue(&paddleQueue,&msg,WICED_WAIT_FOREVER);
switch(msg.evt)
{
case MSG_POSITION:
if(gameState == GS_RUNNING)
paddle0_desire_pos = msg.val/2;
if(gameState == GS_OVER)
{
paddle0_desire_pos = msg.val/2;
updatePaddle(PADDLE_ABSOLUTE);
}
break;
case MSG_BUTTON0:
if(gameState == GS_OVER || gameState == GS_START)
startGame();
break;
case MSG_BUTTON1:
break;
}
}
}