AD840X.cpp

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// Copyright (c) 2024 anabrid GmbH
// Contact: https://www.anabrid.com/licensing/
//
// SPDX-License-Identifier: MIT OR GPL-2.0-or-later
 
#include "AD840X.h"
 
const SPISettings functions::AD8402::DEFAULT_SPI_SETTINGS{4'000'000, MSBFIRST, SPI_MODE3};
 
functions::AD8402::AD8402(bus::addr_t address, uint8_t alt_function_idx)
    : functions::DataFunction(address, alt_function_idx, DEFAULT_SPI_SETTINGS) {}
 
bool functions::AD8402::write_channel_raw(uint8_t ch, uint8_t raw) {
  if (ch > 1)
    return false;
  transfer16(ch << 8 | raw);
  return true;
}
 
const SPISettings functions::AD8403::DEFAULT_SPI_SETTINGS{100'000, MSBFIRST, SPI_MODE0};
 
functions::AD8403::AD8403(bus::addr_t address, uint8_t alt_function_idx)
    : functions::DataFunction(address, alt_function_idx, DEFAULT_SPI_SETTINGS) {}
 
bool functions::AD8403::write_channel_raw(uint8_t ch, uint8_t raw) {
  // The chip has a 10 bit shift register for receiving [2 bit address][8 bit value].
  // The address bits must be sent first, followed by the value bits.
  // When addressing (=CS) is disabled, the received command word is applied.
  // Since we always send 16 bits, we must send 6 "empty" bits and have the command word in the last 10 bits we
  // send.
  if (ch > 3)
    return false;
  auto data_out = ch << 8 | raw;
  transfer16(data_out);
 
#ifdef ANABRID_PEDANTIC
  // We also need to consider the shifting of bits when we send the data the second time in PEDANTIC mode.
  // While we send the 6 empty bits, the previous data inside the shift register is already being clocked out.
  // That means that the first 10 bits of data being read back are the last 10 bits we sent in.
  auto read_back = transfer16(data_out);
  return (read_back >> 6) == data_out;
#else
  return true;
#endif
}