Month: March 2016

The Creek: PSoC 4 Creator Schematic + Firmware

In this post I will describe the PSoC Creator schematic and firmware that I built to run the PSoC4. You can find the project on github. After you open the project in PSoC Creator you will find two projects in the workspace explorer:

p4ardino-creek: This project starts running 10 seconds after the chip powers up. It uses PSoC Analog to Digital Convertor to read the pressure sensor and the temperature sensor. It then convert the data to a readable form and stores it into the EZI2C buffer to be read by the Raspberry PI.
p4bootloader: This project runs for 10 seconds when the chip is rebooted. If it detects the Raspberry Pi host trying to load new firmware it will “bootload”. If after 10 seconds it doesn’t hear anything, it will run the p4arduino-creek application. I will describe how the bootloader works in the next post.

p4ardunio-creek

The schematic for this project contains four sections

The Analog to Digital convertor and the “external” schematic of the pressure current loop. The elements in blue are external to the PSoC and are there just for documentation.
The Red and Blue LED pins and the clock that drives the Red LED to blink
The EZI2C which serves as the I2C Slave for the Raspberry Pi to read
The Bootloadable component which allows this project to be boot loaded.

The configuration of each of elements is show below.

The ADC is configured to run as slowly as possible (1000 SPS). I have also enabled the averaging which automatically averages 256 samples. This effectively makes a low pass filter to remove noise. This is possible because the pressure and temperature move very slowly as compared to the speed at which they are sampled. The SAR ADC in the PSoC is inherently differential, I tell the ADC that I want the negative channel to be connected to a stable VREF. This allows me to measure between 0V and 2*vref = 2.048 volts.

On the ADC channels TAB I enable two channels, both single ended, both with averaging turned on. Channel 0 is connected to the pressure sensor (on Arduino pin A0 = PSoC Pin P2[0]) and channel 1 is connected to the TMP036 (on Arduino pin A1 = PSoC Pin P2[1])

For this design I setup the PSoC4 to act as an EZI2C slave. EZI2C means that the chip follows the EEPROM protocol which many many I2C masters understand. The only thing that I configure in this case is to use the slave address of 0X08.

For this project to be compatible with a bootloader it needs the bootloadble component instantiated. In this case I use all of the default configurations. When I make changes to the firmware in the future I will up-rev the version numbers. These settings are here to prevent you from accidentally overwriting and newer rev of the firmware or putting in the wrong application type.

In order for the bootloadable to work I need to tell it where its “bootloader” image resides. Remember from above that I put both projects in the same workspace. So, what I need to do is browse through the directory hierarchy into the bootloader project and selects its ELF and HEX files. If you want to read more about PSoC4 Bootloading you can read AN86526 entitled “PSoC 4 I2C Bootloader”

One of the unique features of a PSoC is its ability to do hardware based design. In this design I want a slowly blinking LED to indicate that the system is running. For this task I have to configure the pin to let one of the internal clocks drive it. To make this work you need to selected the output mode as “Clock”.

And you need to selected the “Out clock” as external.

Now, I want to turn off the Blue LED. As the LED is active Low, to turn it off you write a 1 to the pin. I do this as part of the setup of the pin by setting the initial drive state to high.

The last step in the device configuration is to select the proper pins on the Design Wide Resources (DWR) pins tab. Not setting the pins correctly is one of the most frequent errors that users make with PSoC Creator.

The firmware for the project is simple. In the first section (lines 3-8) I define a packed structure to serve as the I2C buffer. The __attribute__((packed)) tells the compiler to put all of the members of the structure in contiguous bytes. In the structure I defined below, if I had not marked it is packed, it is likely that the compiler would have put two bytes of padding after the pressureCounts and two bytes after the centiTemp. It would have done this to work align those datatypes to make the memory access more efficient.

The next section (lines 17-23) I initialize the system and start the components.

The the main body of the program (lines 27-43) I ask the ADC if it is done reading the voltages, if not go on, if so then calculate the different values and store them in the I2C buffer. The “CyEnterCriticalSection” prevents an I2C interrupt from reading the buffer before the data is completely written to prevent a partial read of the data.

In the next post I will explain boot loading and the p4bootloader project.

Index	Description
The Creek: IOT for the Elkhorn Creek	Introduction
The Creek: Solution Architecture 1.0	Overall architecture
The Creek: Creek Board 1.1	Eagle layout of the board
The Creek: Creek Board 1.0 – RCCA	A discussion of the errors in the 1.0 board
The Creek: CYPI, a Raspberry Pi to Arduino Bridge	PSoC4 <--> Raspberry Pi Bridge Board
The Creek: PSoC4 Creator Schematic and Firmware	Firmware to interface with the temperature and pressure sensors
The Creek: Testing the Firmware	Using tools to verify that the PSoC 4 Firmware is working correctly
The Creek: Testing the Bootloader	Make sure that you can load new firmware into the PSoC
The Creek: Software Architecture	All of the Raspberry Pi software connections
The Creek: Install MySql	Instruction to configure MySql
The Creek: Install Tomcat	Instruction to configure Tomcat JSP Server
The Creek: Data Collection Java (Part 1)	The Java program that reads the I2C and saves it in the database
The Creek: Data Collection Java (Part 2)	The Java program that reads the I2C and saves it in the database
The Creek: Create the Chart with JFreeChart	Using open source Java charting software to create plots of the Creek Depth
The Creek: Flood Event Data Processor	A batch program to create analyze the database and create a table of flood events
The Creek: Flood Event Web Page	A batch program to create the flood event web page
The Creek: Creek Server 1.1	Updates to all of the back off server programs to integrate charts
The Creek: JSP Web Page for www.elkhorn-creek.org	The JSP program to make the table and display the website
The Creek: Raspberry Pi Clock Stretching	Sorting out a bug in the system having to do with the Broadcomm Raspberry Pi Master not functioning well with clock stretching
The Creek: Creek Server 1.2	Caching the web pages to make them faster

PSoC4000s & The SmartIO – Part 5

This is my last post on the SmartIO. This time, I am going to describe how to use the SmartIO to trigger an interrupt. For this project I will start from the “SmartIOCountUp” project. That project is a 3-bit counter. I thought that I would choose one of the states (000) and trigger an interrupt when that state is hit, then toggle the P25 user led. I will keep data4, and gpio 3,6,7 exactly the same. I will use gpio 2 to trigger the interrupt, which can be accomplished by setting it up as an output. Here is the SmartIO configuration:

The next step is to use LUT2 to look for the “000” state and to create a rising edge. The other states will be 0.

After making the modification to the SmartIO the next step is to fix the schematic. To do this I add a pin for P22, its configuration is on the next screen. In addition I move the P25 (aka the BlueLED on the master board) to pin by itself.

To configure the P22 pin. There is a trick that is required to make the pin be both an output, so that it can be connected to the SmartIO LUT as well as an Input, so that it can be connected to the Port 2 interrupt.

After setting up the pin to be both an Input and an Output you need to configure the pin to have an interrupt on the rising edge.

Then I assign the pins.

The last step is to make the firmware.

Lines 4-9 create an interrupt service routine
Line 18 registers the interrupt service routine to be called with the Port2 interrupt is triggered
The rest is the same as before

When I run this, I see the Blue LED toggle each time it gets to state 000 (which is all three LEDs on as they are active low).

You can find this PSoC Creator workspace on github in the directory called “SmartIO”. This project is called “SmartIOInterrupt”.

Index	Description
PSoC4000s & The SmartIO – Part 1	An introduction to the SmartIO and first project
PSoC4000s & CSX Mutual CapSense Buttons Part 1	Using mutual capacitance
PSoC4000s & CSX Mutual CapSense Buttons Part 2	Using the CapSense tuner
PSoC4000s & The SmartIO – Part 2	A 3 input XOR logic gate
PSoC4000s & The SmartIO – Part 3	A 3 bit up counter state machine
PSoC4000s & The SmartIO – Part 4	Using an external clock with the Smart IO
PSoC4000s & The SmartIO – Part 5	Triggering an interrupt

SmartIO

PSoC4000s & The SmartIO – Part 4

In the previous post I built a 3-bit counter that is clocked by the PWM. In this example I will show you how to make the same design work with an external clock. It seems like it would be cool to use the CapSense Button to provide the clock. I will start by copying SmartIOCountUp to a new project called SmartIOCountUpExtClock.

First, I delete the clock and PWM. Then add a new digital output pin (P20) that I can toggle from the CapSense handler and a digital Input pin (P21) to clock the SmartIO. I add a wire between them on the female header on the board.

The next step is to modify the SmartIO. I change data4 and data5 to bypass. Then make gpio1 an input and then set the Clock to gpio1. Here is what the new SmartIO configuration looks like:

And the schematic.

Assign the pins.

I need to update the main.c write the CapSense button to P20 to be a clock source for the SmartIO

After I program the board, I can “clock” my statemachine with CapSense Button2. Cool. Obviously this example is a bit contrived in that I am running a wire on the outside of the chip, but you could imagine that you might have a “real” example that uses an onboard clock source.

You can find this PSoC Creator workspace on github in the directory called “SmartIO”. This project is called “SmartIOCountUpExtClock”.

Index	Description
PSoC4000s & The SmartIO – Part 1	An introduction to the SmartIO and first project
PSoC4000s & CSX Mutual CapSense Buttons Part 1	Using mutual capacitance
PSoC4000s & CSX Mutual CapSense Buttons Part 2	Using the CapSense tuner
PSoC4000s & The SmartIO – Part 2	A 3 input XOR logic gate
PSoC4000s & The SmartIO – Part 3	A 3 bit up counter state machine
PSoC4000s & The SmartIO – Part 4	Using an external clock with the Smart IO
PSoC4000s & The SmartIO – Part 5	Triggering an interrupt

SmartIO

PSoC4000s & The SmartIO – Part 3

For this post, I wanted to build a simple state machine inside of the SmartIO. So I decided to build a 3-bit counter. On the CY8CKIT145 board, port 2 is mostly connected to LEDs. When you look at the picture below you can see that the LEDs on the left side of the board are easiest to see, so I decided to use them to indicate the state of the counter. You can see from my notes that I was originally considering using LED9,11,10 which are the three LEDs on the CapSense buttons board. I also considered using LED5,6,8 which are on the right side of the slider board, but I ruled all of that out because they were hard to see.

To build this project you start by creating the schematic. In this case I copied the design from the previous post called “145MutualCap” which had 3 CapSense buttons and 3 LEDs (LED10,11,9). I then added:

A 5 KHz Clock to drive the PWM
A PWM to divide down the clock to a speed that I could see and provide a clock for the counter
A Smart IO
4 Output Pins to drive LEDs (P27, P26, P25, P23)

Next I configured the PWM with a 50% duty cycle and a Period of 10000. This results in a 0.5Hz clock:

Then I configure the SmartIO.

Setup “data4” as an input to the Smart IO. Data 4 is the line out 0 of the TCPWM0
Setup “data5” as an input to the Smart IO. Then configure it to be the “clock” for the smart IO. Data 5 is the Line_N of TCPWM0. Originally I wanted to be able to have the clock drive LED5 as well, but this can create a timing hazard in the Smart IO and is not allowed (which is why I mirror data 4 onto the output P25.
Setup GPIO 7,6,5, and 3 as outputs (these outputs are connected to P27, P26, P23 which are the LEDs on the slider board. GPIO5 is connected to P25 that is the user LED on the main board

Then I configure LUTs 6, 3, 7 to implement the state table of a counter

I want to be able to see the clock (the PWM input data4) ticking so I create a transparent LUT (000 = 0 and 111 = 1) for LUT5 which is attached to P25 which is the LED on the main board.

After this is done I need to assign the Pins.

Followed by the very simple firmware which is copied from the previous design. The only new code is line 9 to turn on the PWM.

You can find this PSoC Creator workspace on github in the directory called “SmartIO”. This project is called “SmartIOCountUp”.

Index	Description
PSoC4000s & The SmartIO – Part 1	An introduction to the SmartIO and first project
PSoC4000s & CSX Mutual CapSense Buttons Part 1	Using mutual capacitance
PSoC4000s & CSX Mutual CapSense Buttons Part 2	Using the CapSense tuner
PSoC4000s & The SmartIO – Part 2	A 3 input XOR logic gate
PSoC4000s & The SmartIO – Part 3	A 3 bit up counter state machine
PSoC4000s & The SmartIO – Part 4	Using an external clock with the Smart IO
PSoC4000s & The SmartIO – Part 5	Triggering an interrupt

SmartIO

PSoC4000s & The SmartIO – Part 2

In the previous posts I introduced you to the Smart IO. I also went through the instructions to create CapSense Buttons using the new Mutual-cap CSX mode of the PSoC4000S. In this post I am going to use the three CapSense buttons on the CY8CKIT-145 as inputs to the Smart IO. I want to create a simple logic function P25 = !XOR(P24,P26,P27). This will cause the LED that is attached P25 to light up when there is an odd number of 1’s on P24,P26,P27. The equation is slightly strange because the LED is wired as active low (it lights up when there is a 0 written to it)

To make this work I soldered an 8 pin female header to Port 2 of my development kit. I then wired:

P20 <–> P24
P21 <–> P26
P22 <–> P27

You can see all of that in the picture below.

The next step is to create the schematic for this design. I started from the Mutual Capacitance project that I talked about in the previous post. It has three LEDs and the Capsense Buttons. I then add

Three digital output pins (P20,P21,P22) to drive the three inputs to the SmartIO
Three digital input pins (P24,P26, P27) to use as inputs to the SmartIO
One digital output pin (P25) to drive the LED
The Smart IO block

The next step is to configure the SmartIO. I setup P24,P26,P27 as “inputs” and setup P25 as an “output”

Then I configure the LUT to match the logic equation: P25 = !XOR(P24,P26,P27)

Lastly I assign the pins to the correct physical pins on the chip.

Then I create the firmware by copying the main.c from the earlier CapSense example. I then add the small amount of code to glue it all together:

Line 7: start the SmartIO
Lines 27-29: Write to P20,P21,P22 based on the state of the input buttons.

You can find this PSoC Creator workspace on github in the directory called “SmartIO”. This project is called “3Xor”.

In the next post I will show you how to make a state machine using the Smart IO.

Index	Description
PSoC4000s & The SmartIO – Part 1	An introduction to the SmartIO and first project
PSoC4000s & CSX Mutual CapSense Buttons Part 1	Using mutual capacitance
PSoC4000s & CSX Mutual CapSense Buttons Part 2	Using the CapSense tuner
PSoC4000s & The SmartIO – Part 2	A 3 input XOR logic gate
PSoC4000s & The SmartIO – Part 3	A 3 bit up counter state machine
PSoC4000s & The SmartIO – Part 4	Using an external clock with the Smart IO
PSoC4000s & The SmartIO – Part 5	Triggering an interrupt

SmartIO

PSoC4000s & CSX Mutual CapSense Buttons Part 2

In the previous post I gave you the instructions to get the new Mutual Capacitance buttons going on the CY8CKIT-142. In this post I will talk about how to add the Capsense Tuner to your project. The Capsense tuner can talk to your design while it is running, then report back to you the parametric of your design.

First you need to add the tuner to your project. In order to do this, start with the last design, then add an EzI2C component. Here is the new schematic:

Then you configure the EZ2IC to have 16 bit sub addresses.

Then assign the EZI2C pins to the KitProg I2C bridge pins

The last step is to write the firmware which is almost exactly what you had in the last project except

Lines 8-9 which start the capsense block and setup the Capsense memory buffer to be readable by the remote host
Line 21: which updates the Capsense memory buffer with the current state of the capsense parameters

Once all of this is done, build and program the device. Then start the capsense tuner by right clicking the Capsense component in the schematic and saying “run Tuner”

Then configure the tuner communication parameters from the “Tools->Tuner communication setup” menu. These should match what you have setup in the EZI2C component. Specifically you need set the I2C addresses to be the same, and you need to have the sub-address set to “2-bytes” which is the same as the 16-bit sub-address which you set in the component above.

The next step is to press “connect” and the “start”. First make sure that your three buttons are working. In the picture below you can see that I am touching Buttons 1 and 2 as they are “active” (red color) which means that their signal is above the threshold.

The next step is to look at a “graph view” of button 0. You can do this by pressing “graph view” and selecting Button0_Rx0. Once I switch to this view I touch the button 9 times. You can see that as there are 9 button touches in the Status window. A status of 1 means that the button is active and a status of 0 is an inactive.

In the sensor data window you can see the “baseline” which is the noise on the sensor node without a touch. The blue line is the “RawCounts” which the amount of signal on the node.

In the middle window you can see the “Sensor Signal” which is the Sensor Data minus the baseline. Any time the Sensor Signal is above the touch threshold then the sensor status is active.

The last step is to use the SNR measurement tab to see how robust your design is. First click on the “SNR Measurement” tab. Then pick out which sensor you will measure. In this case I have setup measurement on “Button_0”. Then click on “Acquire noise” and wait. It will make the graph shown below which says that my noise is about 3008-2995 or about 13 counts.

The next step is to see how much signal you get. Start this process by pressing “Acquire Signal” and touching the correct button. You can see orange line represents the amount of signal when you are touching the sensor. The system will then calculate the SNR which in this case is 56.85 which is tons.

The last thing that you could do is change the Capsense parameters in the sensor parameter screen. For instance you could change the threshold from 100 to a bigger number to give more reliable touches.

OK. Now I have my capsense buttons working. In the next posts Ill be ready to talk more about the Smart IO.

You can find this PSoC Creator workspace on github in the directory called “145MutualCap”. This project is called “TunerMutualCapButtons-145”.

Capsense

PSoC4000s & CSX Mutual CapSense Buttons Part 1

In the previous post I talked about my original goal to learn about the SmartIO. But, in order fully try out the SmartIO I needed an input source. On this board I had only one easy input from the factory – specifically the mechanical button on P0[7]- but I wanted to have multiple switches. Well, the obvious choice was to use the three Capsense Buttons on the user interface expansion board. When I looked at that board closely I remembered that the buttons were put there to support the new Capsense functionality of the PSoC4000s family. Inside of Cypress we call the new feature “CSX”, but its real name is “Mutual Capacitance”. Mutual Capsense works by transmitting a signal on the “Tx” pin and then receiving that signal by capacitively coupling that signal through your finger into the “Rx” line. Here is a picture of that part of the PCB schematic and a zoom in of the board. You can see that there are three different size buttons. Each of the buttons is composed of an even number of pie shaped segments.

The mutual capacitance technique has a much higher Signal-to-Noise Ratio (SnR) as compared to the Self Capacitance technique of previous chips and as a result is more immune to noise and can work through a thicker overlay. I thought that I would try putting on overlay on my board, so I cut out a piece of 1.5mm acrylic and used double sided tape to attach it to my board. You can see it in the photograph above.

To make this work I started by creating a new project called “MutualCapButtons”. I then added the Capsense component and three digital output pins (one for each of the three LEDs on the expansion board). Here is the schematic:

The next step was to configure the CapSense block by double clicking it. I then added three buttons and set the sensing mode to CSX (Mutual-cap).

It is possible to have dedicated Tx/Rx pins or you can share the Txs. To do this, select “Advanced” and “Widget details”. Then select “Button1_Tx” and choose its sensor to be the same as “Button0_Tx”. On this design I shared the Tx between all three of the buttons.

The next step is to assign the pins to the correct Port/Pin locations on the chip:

The last step is to write the firmware

Lines 8-10 Start the capsense block and get the scanning going
Line 14: If the capsense block is done scanning then process the results
Line 16: Take all of the raw data from the scan and setup all of the status information
Lines 18-20: If the buttons are being pushed then turn on the corresponding LED
Lines 22-23 Start another scan

That is all there is to making it work.

You can find this PSoC Creator workspace on github in the directory called “145MutualCap”. This project is called “MutualCapButtons-145”.

In the next post Ill talk in detail about using the Capsense Tuner to understand the Capsense performance.

Capsense

PSoC4000s & The SmartIO – Part 1

In the previous four posts I talked about building an IOT device using the new CY8CKIT145. You might remember from the first post that my original objective in picking up the board was to try a new feature of PSoC Creator. Well, over the last few days I have been trying out that feature. Actually, it isn’t a feature of the software, it is a feature of some of the new chips called the Smart IO. The Smart IO is a programmable logic bock that sits between the High Speed IO Matrix (HSIOM) of the chip and the Input/Output Port. The HSIOM has all of the peripherals (SCB, TCPWM etc) of the chips attached to it. The Smart IO will allow you to take signals from inside or outside of the chip, perform logic functions on them, and then drive those signals into or out of the chip. Some of examples of why you might want to do this include:

Combining several inputs (from the outside) to trigger an interrupt
Inverting a signal entering the chip
Inverting a signal exiting the chip
Remapping an input from one pin to a different input (e.g. flipping Tx, Rx pins)
Buffering one signal into multiple output pins (to increase the drive strength)

As usual with Cypress programmable logic, you can do a jaw dropping number of clever things. This block includes sequential logic as well as combinational logic, so it is possible to make state machines in the fabric. It also includes more surprises which have not been shown yet.

The Smart IO works the same as other peripheral blocks, you start by dragging the component onto the schematic and double clicking to start the customizer.

When you start the customizer you get the screen below. The first thing to decide is which Port is going to use the Smart IO. The Smart IO completely takes over an entire port. On this chip there are two Smart IOs, one on Port 2 and one on Port 3. When you look at the customizer there are some things to notice:

On the right side of the customizer you can see the 8 GPIO pins. The dropdown menus that are currently labeled “Bypass” allow you to select the mode of the pin (Bypass, Input, Output, None).
On the bottom of the customizer you can see the 8 LUTs and select their inputs.
On the left side of the customizer you can see the the 8 connections to/from the HSIOM. The drop down menu that is currently labeled “Bypass” allows you to select the mode of that connection to the HSIOM (Bypass, Input, Output, None). I will talk about the “Undefined” menu in the with the next picture
In the middle of the customizer is the routing matrix. Horizontally on the routing matrix there are 8 groups of three wires. The top wire in each group is a wire that originates with the GPIO. The middle wire originates from the corresponding LUT. The bottom wire originates from the HSIOM. For example the top three wires in the picture are
- Line 1: from GPIO7
- Line 2: from LUT 7
- Line 3: from Data7
You can “make” the connection by either by clicking the solder dot or by choosing from the coresponding drop down menu (more on that below)

The other menu on the HSIOM side of the customizer says “Undefined”. This menu has a list of each fixed function device and the inputs/outputs of that device that can be connected to that input/output. This menu doesn’t actually change anything in your design, it is only for information. For example you can see in the screen shot below that data4 can connect to:

TCPWM0: Line_Out
LCD0: COM[20]
LCD0: SEG[20]
SCB1: Spi Select[1]

The best way to show you how all this works is with an example. One of the frustrating things for me in the PSoC 4 Family has always been that the fixed function blocks (TCPWM, SCB) are only allowed to connect to a few pins on the chip. This can be a bit of a pain if you have a board that is already wired and you need to remap a pin. Take for example, on the Cy8CKIT-145 the user LED on the main board is connected to P2[5]. If I want to drive that LED with the Line out (instead of the Line_Out_N) I would create a schematic like this:

When I go to the DWR to assign the pins I would see that the BlueLED cannot be attached to P2[5]. You can see all of the legal placements of that pin because they are highlighted in green.

If I try to do it anyway, I will get the following error when I build.

This error says that I cannot connect the “line” output of the TCPWM to P2[5] (the pin with the LED). That sucks. But, with the Smart IO, I can “remap” the TCPWM Line output to P2[5]. To do this, I will start with a by adding a SmartIO to my schematic and configuring it.

Select Port 2
Configure GPIO 5 to “Output”. This can be done by either clicking on the “solder dot” or by selecting output from the drop down menu
Select data 4 as “Input”
Select data 4 as “TCPWM[0].line. Remember that this is ONLY for your information and doesn’t actually change anything in the project.
Select the 3 inputs to LUT5 to be the data4 line which can be done from the three drop down menus or by clicking the three corresponding solder dots.

Next, I configure the LUT to “passthrough” by setting up 000 = 0 and 111=1 (which are the only two possible combinations as the three inputs are tied together). You change the “Out”s from 0->1 and 1->0 by clicking on it.

Then I will re-wire up the schematic to look like this:

The firmware is trivial, just start the PWM and the SmartIO

When I program the kit the blue LED starts blinking. Cool.

In the next posts I will teach you how to use some other configurations of the Smart IO and how to use the CapSense block to create inputs for the Smart IO.

You can find this PSoC Creator workspace on github in the directory called “SmartIO”. This project is called “SimpleSmartIO”.

Index	Description
PSoC4000s & The SmartIO – Part 1	An introduction to the SmartIO and first project
PSoC4000s & CSX Mutual CapSense Buttons Part 1	Using mutual capacitance
PSoC4000s & CSX Mutual CapSense Buttons Part 2	Using the CapSense tuner
PSoC4000s & The SmartIO – Part 2	A 3 input XOR logic gate
PSoC4000s & The SmartIO – Part 3	A 3 bit up counter state machine
PSoC4000s & The SmartIO – Part 4	Using an external clock with the Smart IO
PSoC4000s & The SmartIO – Part 5	Triggering an interrupt

SmartIO

PSoC4000s and the CY8CKIT145 Stamp Board – Part 4

OK. We’re ready for the big moment: the user test. I was feeling pretty cool. I had spent the week talking to 100s of people and putting on a pretty good show. I was the master of all things PSoC, a geek rockstar. So I programmed the firmware. The slider worked. I was able to connect to the PRoC BLE from my app. But for some stupid reason the the PSoC and PRoC just were not talking and I had no idea why. And to make matters worse, I didn’t have anything I could (easily) use to debug the problem. So much for being the king of PSoC. I assumed that I had firmware bugs. I tried a bunch of different things, single stepping code, trying different pins, etc. But nothing worked. I couldn’t figure it out. It was intensely frustrating to be stuck on the airplane with a broken design.

As soon as I landed in Detroit, I logged in to get my email. I looked for messages from Rajesh (the PSoC Kit Manager) and sure enough, he had emailed me the missing schematic. After digging through the schematic, I found the error.

The connection between the PRoC and PSoC had a 0 Ohm resistor that was “No Load,” meaning the footprint was there, but the board manufacturer had not put on the resistor. This was done so that the pin could be used as a GPIO for something else.

Here is a zoomed-in picture of the PCB:

The good news was, I was only one plane ride and an hour drive from my soldering iron. As soon as I walked in the door, I went straight to my lab.

Now everything works.

There are two morals to this story:

Don’t go to immediately to your lab after being gone for a week, as it really irritates your wife.
Look closely at the schematic.

You can find the PSoC Creator workspace on github in the directory called “capsenseble-145.”

Index	Description
PSoC4000s and the CY8CKIT145 Stamp Board - Part 1	The board and schematics
PSoC4000s and the CY8CKIT145 Stamp Board - Part 2	PSoC4000S Firmware
PSoC4000s and the CY8CKIT145 Stamp Board - Part 3	PRoC BLE Firmware
PSoC4000s and the CY8CKIT145 Stamp Board - Part 4	Debugging the problem

PSoC4000s and the CY8CKIT145 Stamp Board – Part 3

In this post, I will take you through the PRoC BLE schematic and firmware. I describe a very similar version to this in great detail in the video you can find on the Cypress Video Training website.

First, I create a new project in my workspace called “145capsenseled-ble.” Then, I add the UART component (the SCB version) and the BLE component.

Next, I configure the component to be a GATT server with a custom profile and a GAP client.

Then I create a custom service with two characteristics:

The “led” characteristic, which is set up as a uint8 that is writeable and readable.
The “capsense” characteristic, which is set up as uint16 that is readable and has a “notify.”

Next, I configure the UUIDs of the service and characteristics to match what is hard-coded in the iOS app. Then, I add “Client User Descriptions” that describe the characteristics in plain text.

Next I configure the GAP settings, specifically the advertising packet.

I make the pin I assignments, which is just the UART Rx and Tx lines.

Finally, I write the firmware. I started with main. In the infinite loop (line 116), if I have received a byte from other side, then I assign it to the global variable “fingerPos” (line 118). Next, call updateCapsense() (line 119), to update the GATT database with the new value of the slider.

The updateCapsense function:

Lines 31/32 If there is no connection, then don’t update the GATT database.

Lines 33-39 Update the GATT database with the current fingerPosition.

Lines 42-43 If the iPhone side has asked for notification and the position has changed, then send a notification.

Line 44 Save the last position.

The BleCallBack is the most complicated section of firmware. It uses a “switch” statement to handle the different event “cases.” The cases are:

CYBLE_EVT_STACK_ON & CYBLE_EVT_GAP_DEVICE_DISCONNECTED: In either of these cases you want to start the advertising function.
CYBLE_EVT_GATT_CONNECT_IND: When there is a connection made, update the GATT database with the current state of the CapSense and the LED. This allows the iOS side to read the correct values.
CYBLE_EVT_WRITE_REQ: There are two kinds of write requests that are valid.
- CYBLE_LED_CAPSENSE_LED_CHAR_HANDLE: If the remote side writes into the LED value, then send that data to the PSoC4000S via the UART.
- CYBLE_LEDCAPSENSE_CAPSENSE_CAPSENSECCCD: If the remote side has been asked to notify (or un-notify), then save that in the global variable capsenseNotify.

That is all of the firmware.

In the next post, I’ll take you through the debugging I had to do.

You can find the PSoC Creator workspace on github in the directory called “capsenseble-145.”

Index	Description
PSoC4000s and the CY8CKIT145 Stamp Board - Part 1	The board and schematics
PSoC4000s and the CY8CKIT145 Stamp Board - Part 2	PSoC4000S Firmware
PSoC4000s and the CY8CKIT145 Stamp Board - Part 3	PRoC BLE Firmware
PSoC4000s and the CY8CKIT145 Stamp Board - Part 4	Debugging the problem

PSoC4000s and the CY8CKIT145 Stamp Board – Part 2

In the previous post, I unboxed the CY8CKIT145 and showed you the schematics. In this post, I will show you how to build the CapSense firmware that runs on the PSoC4000S. The first decision I needed to make was how to connect the PSoC and the PRoC chips. So I looked at the back of the kit and there was a handy-dandy picture of the schematic in the silkscreen. Here is a zoomed in view:

I didn’t have the schematic on the airplane, but here is a more “schematic” view of the chips on the board.

I knew that the UART source code would be slightly easier, so I picked that as the mechanism to connect the chips. On my computer I had the “capsenseled” workspace from the videos. So, I created a new PSoC4000S project in that workspace called “145capsenseled.” I started with the schematic:

Add the new CapSense component. I am currently running a “nightly build” of PSoC Creator 3.3 that supports the new chip. You can see in the PSoC Creator release I’m using there is a prototype version of the CapSense component.
Add 5 Digital Output Pins under software control to drive the LEDs that are next to the slider
Add 1 Digital Output pin to drive the blue LED
Add a Serial Communication Block (SCB) configured as a UART

Here is a screenshot of the new CapSense component configuration wizard. You can see I added a linear slider and set up the component to use SmartSense full-auto tuning.

After configuring the CapSense, I set up the pin assignments using the DWR:

Then I wrote the firmware, which was pretty straight forward.

10-11 start the CapSense
12 start the UART
16: If the CapSense block is done scanning and is idle, then read the CapSense and do something with it (lines 17 -> 41).
18: figure out where the person is touching
19: if they have actually touched the block
22-26 light up the LEDs
30-35 If there is no touch, then turn off the LEDs.
36-37 start the next scan
38-39: If the UART is not busy… then send the position (0-100) or (0xFF if there is no touch).
41-42: If there is a byte in the UART receive buffer, then light up or turn off the Blue LED. (Notice that the LED is active low so I use the “!” operation to flip the state of the signal.

After that, I programmed the kit and tested it. It seemed like everything was good. In the next post, I’ll show you the schematic and firmware that runs on the PRoC BLE.

You can find the PSoC Creator workspace on github in the directory called “capsenseble-145.”

Index	Description
PSoC4000s and the CY8CKIT145 Stamp Board - Part 1	The board and schematics
PSoC4000s and the CY8CKIT145 Stamp Board - Part 2	PSoC4000S Firmware
PSoC4000s and the CY8CKIT145 Stamp Board - Part 3	PRoC BLE Firmware
PSoC4000s and the CY8CKIT145 Stamp Board - Part 4	Debugging the problem

Capsense PSoC

Month: March 2016

The Creek: PSoC 4 Creator Schematic + Firmware

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PSoC4000s & The SmartIO – Part 5

PSoC4000s & The SmartIO – Part 4

PSoC4000s & The SmartIO – Part 3

PSoC4000s & The SmartIO – Part 2

PSoC4000s & CSX Mutual CapSense Buttons Part 2

PSoC4000s & CSX Mutual CapSense Buttons Part 1

PSoC4000s & The SmartIO – Part 1

PSoC4000s and the CY8CKIT145 Stamp Board – Part 4

PSoC4000s and the CY8CKIT145 Stamp Board – Part 3

PSoC4000s and the CY8CKIT145 Stamp Board – Part 2

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Month: March 2016

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