circuitpython/ports/nrf/common-hal/busio/SPI.c

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/*
* SPI Master library for nRF5x.
* Copyright (c) 2015 Arduino LLC
* Copyright (c) 2016 Sandeep Mistry All right reserved.
* Copyright (c) 2017 hathach
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "shared-bindings/busio/SPI.h"
#include "py/mperrno.h"
#include "py/runtime.h"
#include "nrf.h"
#include "pins.h"
// Convert frequency to clock-speed-dependent value. Return 0 if out of range.
static uint32_t baudrate_to_reg(const uint32_t baudrate) {
uint32_t value;
if (baudrate <= 125000) {
value = SPI_FREQUENCY_FREQUENCY_K125;
} else if (baudrate <= 250000) {
value = SPI_FREQUENCY_FREQUENCY_K250;
} else if (baudrate <= 500000) {
value = SPI_FREQUENCY_FREQUENCY_K500;
} else if (baudrate <= 1000000) {
value = SPI_FREQUENCY_FREQUENCY_M1;
} else if (baudrate <= 2000000) {
value = SPI_FREQUENCY_FREQUENCY_M2;
} else if (baudrate <= 4000000) {
value = SPI_FREQUENCY_FREQUENCY_M4;
} else {
value = SPI_FREQUENCY_FREQUENCY_M8;
}
return value;
}
void common_hal_busio_spi_construct(busio_spi_obj_t *self, const mcu_pin_obj_t * clock, const mcu_pin_obj_t * mosi, const mcu_pin_obj_t * miso) {
// 1 for I2C, 0 for SPI
self->spi = NRF_SPI0;
self->spi->PSELSCK = clock->pin;
self->spi->PSELMOSI = mosi->pin;
self->spi->PSELMISO = miso->pin;
}
bool common_hal_busio_spi_deinited(busio_spi_obj_t *self) {
return self->spi == NULL;
}
void common_hal_busio_spi_deinit(busio_spi_obj_t *self) {
if (common_hal_busio_spi_deinited(self)) {
return;
}
self->spi->PSELSCK = SPI_PSEL_SCK_PSELSCK_Disconnected;
self->spi->PSELMOSI = SPI_PSEL_MOSI_PSELMOSI_Disconnected;
self->spi->PSELMISO = SPI_PSEL_MISO_PSELMISO_Disconnected;
// reset_pin(self->clock_pin);
// reset_pin(self->MOSI_pin);
// reset_pin(self->MISO_pin);
self->spi = NULL;
}
bool common_hal_busio_spi_configure(busio_spi_obj_t *self, uint32_t baudrate, uint8_t polarity, uint8_t phase, uint8_t bits) {
// nrf52 does not support 16 bit
if ( bits != 8 ) return false;
self->spi->ENABLE = (SPI_ENABLE_ENABLE_Disabled << SPI_ENABLE_ENABLE_Pos);
uint32_t config = (SPI_CONFIG_ORDER_MsbFirst << SPI_CONFIG_ORDER_Pos);
config |= ((polarity ? SPI_CONFIG_CPOL_ActiveLow : SPI_CONFIG_CPOL_ActiveHigh) << SPI_CONFIG_CPOL_Pos);
config |= ((phase ? SPI_CONFIG_CPHA_Trailing : SPI_CONFIG_CPHA_Leading ) << SPI_CONFIG_CPHA_Pos);
self->spi->CONFIG = config;
self->spi->FREQUENCY = baudrate_to_reg(baudrate);
self->spi->ENABLE = (SPI_ENABLE_ENABLE_Enabled << SPI_ENABLE_ENABLE_Pos);
return true;
}
bool common_hal_busio_spi_try_lock(busio_spi_obj_t *self) {
bool grabbed_lock = false;
// CRITICAL_SECTION_ENTER()
// if (!self->has_lock) {
grabbed_lock = true;
self->has_lock = true;
// }
// CRITICAL_SECTION_LEAVE();
return grabbed_lock;
}
bool common_hal_busio_spi_has_lock(busio_spi_obj_t *self) {
return self->has_lock;
}
void common_hal_busio_spi_unlock(busio_spi_obj_t *self) {
self->has_lock = false;
}
bool common_hal_busio_spi_write(busio_spi_obj_t *self, const uint8_t *data, size_t len) {
if (len == 0) {
return true;
}
while (len)
{
self->spi->TXD = *data;
while(!self->spi->EVENTS_READY);
(void) self->spi->RXD;
data++;
len--;
self->spi->EVENTS_READY = 0x0UL;
}
return true;
}
bool common_hal_busio_spi_read(busio_spi_obj_t *self, uint8_t *data, size_t len, uint8_t write_value) {
if (len == 0) {
return true;
}
while (len)
{
self->spi->TXD = write_value;
while(!self->spi->EVENTS_READY);
*data = self->spi->RXD;
data++;
len--;
self->spi->EVENTS_READY = 0x0UL;
}
return true;
}