lib/pin_config/pin_config.cc

#include <Arduino.h>
#include <SPI.h>

#include "gonk/pin_config.h"

#define PW_LOG_LEVEL PW_LOG_LEVEL_DEBUG
#define PW_LOG_MODULE_NAME "PinConfig"

#include "pw_log/log.h"

namespace gonk::pin_config {

PinConfig::PinConfig() { flash_spi = SPIClass(FlashMOSI, FlashMISO, FlashCLK); }

void PinConfig::Init() {
  // Set STATUS LED mode and initial state.
  pinMode(StatusLed, OUTPUT);
  digitalWrite(StatusLed, LOW);

  // Default CS pin to output high.
  pinMode(FlashCS, OUTPUT);
  digitalWrite(FlashCS, HIGH);
}

void PinConfig::InitFpgaPins() {
  // Set FPGA reset pin mode and initial state.
  pinMode(ICE40ResetN, OUTPUT);
  digitalWrite(ICE40ResetN, HIGH);

  // Set FPGA configure done signal pin as an input.
  pinMode(ICE40Done, INPUT);
}

void PinConfig::FpgaHalt() {
  // Set FlashCS to signal the FPGA it should load the bitstream from external
  // flash.
  pinMode(FlashCS, INPUT_FLOATING);
  delay(10);

  // Hold in reset for a small amount of time.
  digitalWrite(ICE40ResetN, LOW);
  delay(50);

  // Boot fpga and give it time to reset any internal SPI pin configuration.
  digitalWrite(ICE40ResetN, HIGH);
  delay(10);

  // Finally, hold in reset.
  digitalWrite(ICE40ResetN, LOW);
}

void PinConfig::FpgaSpiConfigMode() {
  // Turn on Flash Hold so it ignores any SPI communication.
  pinMode(FlashHold, OUTPUT);
  pinMode(FlashWP, OUTPUT);
  digitalWrite(FlashHold, LOW);
  digitalWrite(FlashWP, LOW);
  delay(1);

  // Set FlashCS (ICE_SPI_SS) low and pulse ICE40ResetN. This signals the FPGA
  // to boot into SPI config mode.
  pinMode(ICE40ResetN, OUTPUT);
  pinMode(FlashCS, OUTPUT);

  // Pulse ICE40ResetN
  digitalWrite(ICE40ResetN, LOW);
  digitalWrite(FlashCS, LOW);
  delay(10);
  digitalWrite(ICE40ResetN, HIGH);

  // Enalble GPIO control of MOSI, MISO and CLK.
  pinMode(FlashMOSI, OUTPUT);
  pinMode(FlashMISO, OUTPUT);
  pinMode(FlashCLK, OUTPUT);
  delay(1);

  // Send 8 clock pulses.
  for (int i = 0; i < 8; i++) {
    digitalWrite(FlashCLK, LOW);
    delayMicroseconds(100);
    digitalWrite(FlashCLK, HIGH);
    delayMicroseconds(100);
  }
  delay(10);
}

void PinConfig::FpgaEnable() { digitalWrite(ICE40ResetN, HIGH); }

void PinConfig::SPIEnable() {
  // Disable Flash hold and write protect.
  pinMode(FlashHold, OUTPUT);
  pinMode(FlashWP, OUTPUT);
  digitalWrite(FlashHold, HIGH);
  digitalWrite(FlashWP, HIGH);
}

void PinConfig::SPIDisable() {
  pinMode(FlashCS, OUTPUT);
  pinMode(FlashCLK, OUTPUT);
  pinMode(FlashMOSI, OUTPUT);
  pinMode(FlashMISO, INPUT_FLOATING);

  digitalWrite(FlashCS, HIGH);
  digitalWrite(FlashCLK, HIGH);
  digitalWrite(FlashMOSI, HIGH);
}

} // namespace gonk::pin_config