STM32F4 SPI1 working, SPI5 not working? - stm32

Question

I got a STM32 Nucleo-F410RB development board and was able to get my external DAC working with SPI1, both with busy-wait and with DMA. I then designed my own custom PCB, built it and was able to flash it. During the design phase I switched from using SPI1 to SPI5 because I needed the SPI1 pins for other functions. But I couldn't get SPI5 to work in my new design - no signal on the SCK and MOSI pins. When I changed my code to use SPI1, I see signals on the respective SPI1 SCK and MOSI pins.
I went back to my Nucleo board and have the same problem - SPI1 works fine but SPI5 doesn't work at all. I'm using Eclipse with the ARM GNU compiler and the most recent version of the Standard Peripheral Library (not HAL).
SPI init function:
void init_spi(void) {
//initialize MOSI and SCK pins
//initialize SPI
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
GPIO_InitTypeDef gpio_init;
gpio_init.GPIO_Pin = GPIO_Pin_0; //SCK
gpio_init.GPIO_Speed = GPIO_Fast_Speed;
gpio_init.GPIO_Mode = GPIO_Mode_AF;
gpio_init.GPIO_OType = GPIO_OType_PP;
gpio_init.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOB, &gpio_init);
gpio_init.GPIO_Pin = GPIO_Pin_8; //MOSI
gpio_init.GPIO_Speed = GPIO_Fast_Speed;
gpio_init.GPIO_Mode = GPIO_Mode_AF;
gpio_init.GPIO_OType = GPIO_OType_PP;
gpio_init.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOB, &gpio_init);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource0, GPIO_AF_SPI5);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_SPI5);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
//initialize DAC CS PIN
gpio_init.GPIO_Pin = DAC_CS_PIN;
gpio_init.GPIO_Speed = GPIO_Fast_Speed;
gpio_init.GPIO_Mode = GPIO_Mode_OUT;
gpio_init.GPIO_OType = GPIO_OType_PP;
gpio_init.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA, &gpio_init);
SPI_I2S_DeInit(SPI5);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI5, ENABLE); //enable SPI clock
SPI_InitTypeDef spi_init;
spi_init.SPI_Direction = SPI_Direction_1Line_Tx;
spi_init.SPI_Mode = SPI_Mode_Master;
spi_init.SPI_DataSize = SPI_DataSize_8b; //8b? Need to clock in 24 bits of data per DAC channel
spi_init.SPI_CPOL = SPI_CPOL_Low; //5134 uses low to high and high to low clock transitions. ie. idle state is LOW
spi_init.SPI_CPHA = SPI_CPHA_2Edge; //clock phase - data is clocked on falling edge of clock pulse
spi_init.SPI_NSS = SPI_NSS_Soft; //DAC chip select is handled in software
spi_init.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_2; //APB2 clock/2, so 25 MHz SPI clock speed
spi_init.SPI_FirstBit = SPI_FirstBit_MSB; //check datasheet
spi_init.SPI_CRCPolynomial = 7; //what is this?
SPI_Init(SPI5, &spi_init);
SPI_Cmd(SPI5, ENABLE);
}
SPI Write function:
void spi_write_dac(uint16_t value, uint8_t channel) { //currently just use busy/wait to transmit data to test DAC
uint8_t dac_low = value & 0xFF; //take bottom 8 bits
uint8_t dac_high = value >> 8; //take top 8 bits
GPIO_ResetBits(GPIOA, DAC_CS_PIN); //CS low
while (SPI_I2S_GetFlagStatus(SPI5, SPI_I2S_FLAG_TXE) == RESET);//wait for empty buffer
SPI_I2S_SendData(SPI5, channel); //send control byte
while (SPI_I2S_GetFlagStatus(SPI5, SPI_I2S_FLAG_BSY) == SET); //wait for byte to be sent
SPI_I2S_SendData(SPI5, dac_high); //send first data byte
while (SPI_I2S_GetFlagStatus(SPI5, SPI_I2S_FLAG_BSY) == SET); //wait for byte to be sent
SPI_I2S_SendData(SPI5, dac_low); //send second data byte
while (SPI_I2S_GetFlagStatus(SPI5, SPI_I2S_FLAG_BSY) == SET); //wait for byte to be sent
GPIO_SetBits(GPIOA, DAC_CS_PIN);
}
This code does not work but when I change all SPI5 references to SPI1 and use PB3 for SCK and PB5 for MOSI then SPI is working. I've checked the SPI control registers and they look like they are correctly configured for SPI5 so I'm starting to get to my wit's end.
Why will SPI1 work fine on both my own design and on the Nucleo board, but SPI5 will not work on either board?

Answer 1

That is easy answer. SPI5 is not mapped to PB3 and PB5...
If you look at the datasheet on page 39 (datasheet rev 5), you could see that:
On PB3 you can use JTDO-SWO, I2C4_SDA, SPI1_SCK/I2S1_CK, USART1_RX, I2C2_SDA, EVENTOUT, but no SPI5
On PB5, you can use LPTIM1_IN1, I2C1_SMBA, SPI1_MOSI/I2S1_SD, EVENTOUT, but no SPI5
If you really want to use SPI5, you can use the following IOs:
SPI5_MISO: PA12
SPI5_MOSI: PA10 or PB8
SPI5_SCK: PB0

Answer 2

I did the same mistake.
GPIO_PinAFConfig(GPIOB, GPIO_PinSource0, GPIO_AF_SPI5);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_SPI5);
GPIO_AF_SPI5 must be GPIO_AF6_SPI5 for STM32F410.
#define GPIO_AF6_SPI5 ((uint8_t)0x06) /* SPI5 Alternate Function mapping (Only for STM32F410xx/STM32F411xE Devices) */

Answer 3

Is the SPI_I2S_DeInit(SPI1); normal in your init_spi() function when all your references are for SPI5 peripheral ?
If I am not wrong the target STM32 is a STM32F410RBT6. I let here the Datasheet and Reference Manual for future purposes :
STM32F410RBT6 Datasheet
STM32F410RBT6 Reference Manual