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pico-ice

ice_spi.h

SPI library exclusive to the main SPI bus between the RP2040 and the various other board components, including the iCE40 CRAM, iCE40 hardened SPI core, SRAM chip, FLASH chip.

void ice_spi_init(void)

Configure the GPIO pins of the SPI library to high-impedance to let others access the bus, such as the iCE40 during initial configuration.

void ice_spi_chip_select(uint8_t csn_pin, bool active_high)

  • csn_pin - user-selectable GPIO pin to assert (set to LOW voltage level)
  • active_high - true for active-high chip-select pin, false for active-low

Also set the SPI TX and SCK pins to output/drive mode, and keeps the RX pin to input/high-z mode.

void ice_spi_chip_deselect(uint8_t csn_pin)

  • csn_pin - user-selectable GPIO pin to assert (set to LOW voltage level)

Also set the SPI TX and SCK pins back to input/high-z mode.

void ice_spi_write_async(uint8_t const *buf, size_t len, void (*callback)(volatile void *), void *context)

  • buf - buffer to send over SPI.
  • len - size of that buffer.
  • callback - function called at the end of the transfer.
  • context - argument passed to that function.

Wait previous transfer completion if any and enqueue a new one in the background (interrupt-driven). If callback is NULL, then nothing will be done.

void ice_spi_read_async(uint8_t tx, uint8_t *buf, size_t len, void (*callback)(volatile void *), void *context)

  • tx - byte to send conotinuously while readying
  • buf - buffer to fill from SPI.
  • len - size of that buffer.
  • callback - function called at the end of the transfer.
  • context - argument passed to that function.

Wait previous transfer completion if any and enqueue a new one in the background (interrupt-driven). If callback is NULL, then nothing will be done.

bool ice_spi_is_async_complete(void)

Return true if an SPI transfer is ongoing, false if ready to enqueue another.

void ice_spi_await_async_completion(void)

Waits until SPI transfer completion.

void ice_spi_read_blocking(uint8_t tx, uint8_t *buf, size_t len)

  • tx - byte to send conotinuously while readying
  • buf - buffer to fill from SPI.
  • len - size of that buffer.

Blocking version of ice_spi_read_async().

void ice_spi_write_blocking(uint8_t const *buf, size_t len)

  • buf - buffer to send over SPI.
  • len - size of that buffer.

Blocking version of ice_spi_write_async().