Before I write down my problem let me say that I have literally visited all relevant pages on internet regarding RPi4B, SPI, BMI088, bcm2835 library and C, with no luck and a lot of frustration.
I have 6 BMI088 sensors I'd like to connect to RPi4B over SPI. On Arduino it works perfectly (one or all 6) with Bolder Flight library. The problem is I don't get anything from sensor when I connect it to RPi. Connections are ok (3.3 V, GND, MISO, MOSI, SCK, CS, PS to ground (only BMI088)). I also have a switch to turn sensor power ON/OFF. I am sending exactly the same messages as Arduino library does, but I get nothing from the sensor, MISO is silent. I provide a rising edge to CSB1 pin as stated in datasheet. If I connect MISO and MOSI RPi receives data.
How do I get BMI088 to talk to RPi over SPI?
The code (not whole, just relevant part):
#include <bcm2835.h>
#include <stdio.h>
#define CS_PIN 25
unsigned char buffer[7] = {0};
int main(int argc, char *argv[])
{
int x1, x2, y1, y2, z1, z2;
if (!bcm2835_init())
{
printf("bcm2835_init failed.\n");
return 1;
}
if (bcm2835_init())
{
printf("bcm2835_init successful.\n");
}
if (!bcm2835_spi_begin())
{
printf("bcm2835_spi_begin failed.\n");
return 1;
}
if (bcm2835_spi_begin())
{
printf("bcm2835_spi_begin successful.\n");
}
bcm2835_spi_setBitOrder(BCM2835_SPI_BIT_ORDER_MSBFIRST); // The default
bcm2835_spi_setDataMode(BCM2835_SPI_MODE0); // The default
bcm2835_spi_setClockDivider(BCM2835_SPI_CLOCK_DIVIDER_1); // The default
bcm2835_spi_chipSelect(BCM2835_SPI_CS_NONE); // The default
//bcm2835_spi_setChipSelectPolarity(BCM2835_SPI_CS0, LOW); // the default
bcm2835_gpio_fsel(CS_PIN, BCM2835_GPIO_FSEL_OUTP); //CS is an output
bcm2835_gpio_clr(CS_PIN);
delayms(100);
while(1)
{
// chip ID
buffer[0] = 0x00; //ACC_CHIP_ID;
//buffer[1] = 30;
bcm2835_spi_transfer(0x00);
bcm2835_delayMicroseconds(100);
bcm2835_gpio_set(CS_PIN);
bcm2835_delayMicroseconds(100);
bcm2835_gpio_clr(CS_PIN);
bcm2835_spi_transfern(buffer, 1);
bcm2835_delayMicroseconds(100);
bcm2835_gpio_set(CS_PIN);
printf("\n\nID:\t0x%02X\t0x%02X\n", buffer[0], buffer[1]);
delayms(100);
// soft reset
buffer[0] = 0x7E;
buffer[1] = 0xB6;
bcm2835_spi_transfern(buffer, 2);
delayms(100);
printf("RESET:\t0x%02X\t0x%02X\n", buffer[0], buffer[1]);
delayms(100);
// set power
buffer[0] = 0x7D;
buffer[1] = 0x04;
bcm2835_spi_transfern(buffer, 2);
printf("POWER:\t0x%02X\t0x%02X\n", buffer[0], buffer[1]);
delayms(100);
// set mode
buffer[0] = 0x7C;
buffer[1] = 0x03;
bcm2835_spi_transfern(buffer, 2);
printf("MODE:\t0x%02X\t0x%02X\n", buffer[0], buffer[1]);
delayms(100);
// set range
buffer[0] = 0x41;
buffer[1] = 0x03;
bcm2835_spi_transfern(buffer, 2);
printf("RANGE:\t0x%02X\t0x%02X\n", buffer[0], buffer[1]);
delayms(100);
// set ODR
buffer[0] = 0x40;
buffer[1] = 0xAC;
bcm2835_spi_transfern(buffer, 2);
printf("RANGE:\t0x%02X\t0x%02X\n", buffer[0], buffer[1]);
delayms(100);
buffer[0] = 0x12;
buffer[1] = 0x13;
buffer[2] = 0x14;
buffer[3] = 0x15;
buffer[4] = 0x16;
buffer[5] = 0x17;
bcm2835_spi_transfern(buffer, 7);
x1 = buffer[1];
x2 = buffer[2];
y1 = buffer[3];
y2 = buffer[4];
z1 = buffer[5];
z2 = buffer[6];
printf("X:%d %d\tY:%d %d\tZ:%d %d\n", x1, x2, y1, y2, z1, z2);
delayms(500);
}
}
libiiois your friend. - 0andriy