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Nucleo-F103RB and Adafruit C1188 SPI doesn't work

MPasz.2
Associate

Hi,

I have small problem with connecting external sensor to my F103RB NUCLEO board. Im trying to connect Adafruit CAP1188 module through SPI normal mode. I send example messages and dont seem to get the right answer(I get 0). I just want to check if everything works correctly and then I want to start writing the proper program. I think there might be a problem with my spi config. Im begginer at programming STM32. Can anyone check my code and help me fix potential problems? Im steering CS pin through PIN_0 on my NUCLEO.

According documentation reading byte 51h should return C8h

#include "stm32f10x.h"
#include <stdio.h>
 
uint8_t spi_sendrecv(uint8_t byte)
{
 // wait for input buffer
 while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
 SPI_I2S_SendData(SPI1, byte);
 
 // wait for output buffer
 while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
 return SPI_I2S_ReceiveData(SPI1);
}
 
uint8_t read_reg()
{
 GPIO_ResetBits(GPIOC, GPIO_Pin_0);
 spi_sendrecv(0x7A); //Reset
 spi_sendrecv(0x7A); //Reset
 spi_sendrecv(0x7D); // SET ADDRESS POINTER
 spi_sendrecv(0x51); //ADDRES
 spi_sendrecv(0x7F); // READ
 uint8_t value = spi_sendrecv(0xff); //send random message to recieve answer
 GPIO_SetBits(GPIOC, GPIO_Pin_0);
 return value;
}
 
int main(void)
{
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1,ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
 
	//SCK  MOSI
	GPIO_InitTypeDef gpio;
	GPIO_StructInit(&gpio);
	gpio.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_7; //SCK, MOSI
	gpio.GPIO_Mode = GPIO_Mode_AF_PP; //output push pull
	gpio.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &gpio);
 
	/ MISO
	gpio.GPIO_Pin = GPIO_Pin_6;
	gpio.GPIO_Mode = GPIO_Mode_IN_FLOATING; //input
	GPIO_Init(GPIOA, &gpio);
 
	gpio.GPIO_Pin = GPIO_Pin_0; // CS -> PIN_0
	gpio.GPIO_Mode = GPIO_Mode_Out_PP;
	GPIO_Init(GPIOC, &gpio);
	GPIO_SetBits(GPIOC, GPIO_Pin_0);
 
 
	SPI_InitTypeDef spi;
	SPI_StructInit(&spi);
	spi.SPI_Mode = SPI_Mode_Master; 
	spi.SPI_NSS = SPI_NSS_Soft; //  NSS = CS
	spi.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_16; 
	SPI_Init(SPI1, &spi);
 
	SPI_Cmd(SPI1, ENABLE); 
 
 
	while(1){
		uint8_t result1 = read_reg(); //Checking debug, I see 0x00
	}
}

2 REPLIES 2
Ozone
Lead II

As it seems in the schematics at the Adafruit website, the SPI interface is not broken out to the connectors.

You would have to use I2C.

Edit:

At least not on the same connector.

And the thing about the mode-dependant value for R13 is confusing.

MPasz.2
Associate

At the website it seems that SPI is avaiable, I used this guide - https://learn.adafruit.com/adafruit-cap1188-breakout/wiring

I also tried using CubeMx and HAL libraries, and same result - nothing. Maybe problem with wiring?