FPAA Starter Board

You should have the SPI interface enabled in your Raspberry Pi.

Note: If you don't know how to set that up, you can follow this Sparkfun tutorial.

For simplicity, we will be using python to interface with the SPI pins. There are several python packages that can be used to interact with the SPI pins. This section covers two of them: spidev and pigpio.

spidev comes installed by default and after you enable the SPI interface you should be able to use it right away in your code. spidev is enough to program the FPAA however, if you want to generate the clock to the ACLK with the Pi, you need to use the pigpio package to access the Pi PLL and route the GPCLK to the Pi output pins. pigpio also offers the ability to control the SPI pins.

• Option 1: write the code with pigpio to generate the ACLK and use spidev to read the configuration file and send the data over SPI to the FPAA
• Option 2: use pigpio for everything; to generate the ACLK and read the configuration file and send the data over SPI to the FPAA.

I will leave the code below for both options.

At power-on-reset, the FPAA clears its memory, placing the device in a benign condition. Once this power-on-reset sequence concludes, the device is ready to accept configuration data. The first configuration data set loaded into the device after a reset is called a Primary Configuration.

OTC24000 devices may be reconfigured (without intervening resets) using the Update format described later under Dynamic Reconfiguration.

However, to upload a new configuration data, we need to perform a soft reset before sending the configuration data again to the FPAA.

If you use a different platform to send the configuration data to the FPAA don't forget to add and send the soft reset data sequence first.

reset_config = [0,0,0,0,0,213,1,111,0]

It is not possible to read files from Arduino. With that in mind, we need to save the contents of the ahf file into an array of bytes. DynAMx software can do that for us.

Step 1:

Under you project, go to Dynamic Config -> State-driven Method.

Step 2:

Press the "Complete Chips" button, select your FPAA1 chip and press "Ok".

Steps 3:

Go to the "Transitions" tab and check the FPAA1.

Step 4:

Go to the "Generation" tab, check "Generate C Formatted Configuration Text files" and press the "Generate" button. DynAMx will generate the ahf file into an array of bytes formatted in C (the generated file has a txt extension).

Step 5:

We are almost there. The last step requires to change the extension of the file from txt to .h file (change the name of the file too, to a more descriptive name) and add a type and name for the data. In this case we want an array of bytes and write whatever name makes sense for you to use in your application (in this case we called it data).

const byte data[] =
{
0x00, 0x00, 0x00, 0x00, 0x00, 0xD5, 0xB7, 0x20, 
0x01, 0x00, 0x01, 0xC1, 0xC4, 0x00, 0x0E, 0x20,
...

Don't forget to close the parenthesis at the end of the data...

...
0x2A, 0x00
};

We called the file generated by DynAMx on the previous step LP_Test_4MHz.h

Create an Arduino Uno project and add the following code to it:

#include <SPI.h>
#include "LP_Test_4MHz.h"

#define SELb 10
#define ACLK 3

void resetConfig(){
  // State Reconfiguration
  byte msg[9] = {0, 0, 0, 0, 0, 213, 1, 111, 0};

  digitalWrite(SELb, HIGH);
  for(int i=0; i<9; i++){  
    SPI.transfer(msg[i]);
  }
  digitalWrite(SELb, LOW);
}

void sendConfig(){
  // Send Configuration
  digitalWrite(SELb, HIGH);
  /* sizeof is six greater than the size given at the top of the 
   *  text file. This is because six dummy bytes have been added to 
   *  the data, five at the start and one at the end.
   *  */
  for(int i=0; i<(sizeof(data)+6); i++){
    SPI.transfer(data[i]);
  }
  digitalWrite(SELb, LOW);
}

void setup() {
  // Initialize ACLK
  pinMode(ACLK, OUTPUT);
  TCCR2A = 0x23;
  TCCR2B = 0x09;
  OCR2A = 3;
  OCR2B = 1;
  
  // Initialize SPI
  pinMode(SELb, OUTPUT); // set the SS pin as an output

  SPI.begin();
  SPI.setBitOrder(MSBFIRST);
  SPI.setDataMode(SPI_MODE3);
  SPI.setClockDivider(SPI_CLOCK_DIV2);
  
  resetConfig();
  sendConfig();
}

void loop() {
}

GitHub Arduino Code (Link)
GitHub LP_Test_4MHz (Link)

The code presented on the previous section, is generating a clock for the FPAA ACLK at 4 MHz on digital pin 3.

We are also sending the soft reset configuration data sequence first before sending the configuration data stored on the LP_Test_4MHz.h file.

Simulator

Oscilloscope

Simulator

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Simulator

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Simulator

Oscilloscope