Reading MEMS sensor(LIS331HH) from STM32F107 through SPI returns all FF...

saimaddy123 · ‎2011-03-23

Posted on March 23, 2011 at 13:44

saimaddy123 · ‎2011-05-17

Posted on May 17, 2011 at 14:29

I changed GPIO configuration to have MISO to be input floating as mentioned in STM32f10xx reference manual now..I still see

the same behavior. BTW, I am toggling the GPIO connected to SPI2_NSS between ''low'' and ''high'' for every byte read/write.

/* Enable GPIO clock */

RCC_APB2PeriphClockCmd(R_ACC_SPI_GPIO_CLK | RCC_APB2Periph_AFIO , ENABLE);

/* Enable SPI clock */

RCC_APB1PeriphClockCmd(R_ACC_SPI_CLK, ENABLE);

/* Configure SPI pins: SCK, MISO and MOSI */

GPIO_InitStructure.GPIO_Pin = R_ACC_SPI_SCK_PIN | R_ACC_SPI_MOSI_PIN;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(R_ACC_SPI_GPIO_PORT, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = R_ACC_SPI_MISO_PIN;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(R_ACC_SPI_GPIO_PORT, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = R_ACC_SPI_NSS_PIN;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

GPIO_Init(R_ACC_SPI_GPIO_PORT, &GPIO_InitStructure);

SPI_I2S_DeInit(R_ACC_SPI);

/* SPI Config */

SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;

SPI_InitStructure.SPI_Mode = SPI_Mode_Master;

SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;

SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;

SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;

SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;

SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_64;

SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;

SPI_Init(R_ACC_SPI, &SPI_InitStructure);

domen23 · ‎2011-05-17

Posted on May 17, 2011 at 14:29

Is it the correct SPI mode, and frequency?

NSS usually needs to be low for the whole transfer, not just one byte.

Use a scope to check clock, NSS, MOSI, MISO... if only MISO remains high for the whole time, then you might have a defective slave.

drzile86 · ‎2011-05-17

Posted on May 17, 2011 at 14:29

Hi,

I don't see your function or part of code where are you read from this device? Which register are you trying to read? Try to read CTRL_REG1 register which address is 20h and reset value is all 0's and look all signals and clocks on scope,

regards,

saimaddy123 · ‎2011-05-17

Posted on May 17, 2011 at 14:29

Hi,

The issue was with SPI clock...the device worked only with a prescaler value of 32. I should have updated latest status..

Thanks for the comment,

Sai