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PSoC-COMM-Driver

Self-contained implementation of PSoC USBUART/UART component.

Includes 2 FIFO ring buffers for Rx and Tx so we can hold more than the 64 bytes allowed by USBUART.

Data transmission (Rx and Tx) is handled automatically by interrupts at 2kHz (every 0.5ms).

Compatibility

This project has been tested on the following hardware:

  • PSoC 4 (CY8C4244AZI-443)
  • PSoC 5LP (CY8C5888LTI-LP097)

References

This project uses a simple C ring buffer implementation (provided in src/): https://github.com/dhess/c-ringbuf.

The design of this project is based on the following code: https://github.com/noritan/Design307.

Example (main.c)

The following code shows how to do an echo with the 3 different types of messages available.

#include <project.h>
#include "comm_driver.h"

int main(void)
{
    uint8 count = 0;
    uint8 received_data[64];    // Arbitrary array size

    // Initializations
    CyGlobalIntEnable;  // Enable global interrupts
    comm_init();     // Start and setup the COMM driver

    // Application
    for(;;) {
        // Single character
        count = comm_getch(received_data);
        if(count)
            comm_putch(received_data);
        
        // Line of characters (a line ends with COMM_LINE_TERMINATOR)
        count = comm_getline(received_data);
        if(count)
            comm_putline(received_data, count);
        
        // Custom message (see comm_driver_msg.h)
        count = comm_getmsg(received_data);
        if(count)
            comm_putmsg(received_data, count);
    }
}

Setup

TopDesign

Add the following components:

  • 1 x USBUART or UART (named 'COMM')

USBUART component configuration

Descriptor Root = "Manual (Static Allocation)"

Clocks configurations for USBUART (.cydwr)

  • IMO = 24MHz
  • ILO = 100kHz
  • USB = 48Mhz (IMOx2)
  • PLL = 79.5MHz (or as high as you want the MASTER_CLK to be)

Clocks configurations for UART (.cydwr)

  • SysClk > COMM_INTERRUPT_FREQ

Macros (see comm_driver.h)

  • Size of the ring buffers (Rx and Tx): see <RX/TX>_BUFFER_SIZE

System configurations (.cydwr)

  • Heap Size (bytes) = RX_BUFFER_SIZE + TX_BUFFER_SIZE + 2 bytes

    (+ 512 bytes if you use 'sprintf' in your project)

    (+ any more heap required for your application)

Libraries

You will need to add the 'math' library to the linker. Not doing so will not show any errors during compilation or runtime, but the communication may still not work without any indications of what's wrong. Here are the steps:

  1. Right-click on your project in the 'Workspace Explorer' and click on 'Build Settings...'.
  2. In the left panel of the window, find the 'Linker' item. It should be inside the compiler item (which can look like 'ARM GCC 5.4-2016-q2-update').
  3. In the 'Additional Libraries' field, simply add the letter 'm' (lower case).
  4. Done! Click 'OK' to save your changes and close the window.

Custom messages

If you want to send/receive messages with a custom structure, make sure this line is uncommented:

#include "comm_driver_msg.h"

And fill in the information in the file comm_driver_msg.h.

Otherwise, you can comment the line mentionned previously and it will deactivate all the functions related to custom messages.