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// SPI functions on STM32F1
//
// Copyright (C) 2018 Grigori Goronzy <greg@kinoho.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include "command.h" // shutdown
#include "gpio.h" // spi_setup
#include "sched.h" // sched_shutdown
#include "stm32f1xx_ll_gpio.h" // LL_GPIO_SetPinMode
#include "stm32f1xx_ll_rcc.h" // __LL_RCC_CALC_PCLK1_FREQ
#include "stm32f1xx_ll_spi.h" // LL_SPI_Enable
static void spi_set_mode(SPI_TypeDef *spi, uint8_t mode)
{
switch (mode) {
case 0:
LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_LOW);
LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_1EDGE);
break;
case 1:
LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_LOW);
LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_2EDGE);
break;
case 2:
LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_HIGH);
LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_1EDGE);
break;
case 3:
LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_HIGH);
LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_2EDGE);
break;
}
}
static void spi_set_baudrate(SPI_TypeDef *spi, uint32_t rate)
{
const uint32_t pclk = __LL_RCC_CALC_PCLK1_FREQ(SystemCoreClock
, LL_RCC_GetAPB1Prescaler());
const uint32_t prescaler = pclk / rate;
uint32_t setting = LL_SPI_BAUDRATEPRESCALER_DIV256;
if (prescaler <= 2)
setting = LL_SPI_BAUDRATEPRESCALER_DIV2;
else if (prescaler <= 4)
setting = LL_SPI_BAUDRATEPRESCALER_DIV4;
else if (prescaler <= 8)
setting = LL_SPI_BAUDRATEPRESCALER_DIV8;
else if (prescaler <= 16)
setting = LL_SPI_BAUDRATEPRESCALER_DIV16;
else if (prescaler <= 32)
setting = LL_SPI_BAUDRATEPRESCALER_DIV32;
else if (prescaler <= 64)
setting = LL_SPI_BAUDRATEPRESCALER_DIV64;
else if (prescaler <= 128)
setting = LL_SPI_BAUDRATEPRESCALER_DIV128;
LL_SPI_SetBaudRatePrescaler(spi, setting);
}
static void spi_init_pins(void)
{
LL_GPIO_SetPinMode(GPIOB, LL_GPIO_PIN_13, LL_GPIO_MODE_ALTERNATE);
LL_GPIO_SetPinMode(GPIOB, LL_GPIO_PIN_14, LL_GPIO_MODE_INPUT);
LL_GPIO_SetPinMode(GPIOB, LL_GPIO_PIN_15, LL_GPIO_MODE_ALTERNATE);
LL_GPIO_SetPinOutputType(GPIOB, LL_GPIO_PIN_13, LL_GPIO_OUTPUT_PUSHPULL);
LL_GPIO_SetPinPull(GPIOB, LL_GPIO_PIN_14, LL_GPIO_PULL_UP);
LL_GPIO_SetPinOutputType(GPIOB, LL_GPIO_PIN_15, LL_GPIO_OUTPUT_PUSHPULL);
}
struct spi_config
spi_setup(uint32_t bus, uint8_t mode, uint32_t rate)
{
if (bus > 0 || !rate)
shutdown("Invalid spi_setup parameters");
spi_init_pins();
SPI_TypeDef spi_hw = { };
LL_SPI_SetNSSMode(&spi_hw, LL_SPI_NSS_SOFT);
LL_SPI_SetMode(&spi_hw, LL_SPI_MODE_MASTER);
spi_set_mode(&spi_hw, mode);
spi_set_baudrate(&spi_hw, rate);
LL_SPI_Enable(&spi_hw);
return (struct spi_config){ .spi_cr1 = spi_hw.CR1 };
}
void
spi_prepare(struct spi_config config)
{
SPI2->CR1 = config.spi_cr1;
}
void
spi_transfer(struct spi_config config, uint8_t receive_data,
uint8_t len, uint8_t *data)
{
while (len--) {
LL_SPI_TransmitData8(SPI2, *data);
while (!LL_SPI_IsActiveFlag_TXE(SPI2));
while (!LL_SPI_IsActiveFlag_RXNE(SPI2));
uint8_t rdata = LL_SPI_ReceiveData8(SPI2);
if (receive_data) {
*data = rdata;
}
data++;
}
while (LL_SPI_IsActiveFlag_BSY(SPI2));
LL_SPI_Disable(SPI2);
}
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