S32KのトピックRe: S32K144 i2c bmi270 problem

S32K144 i2c bmi270 problem

vinmotion — Sun, 14 Dec 2025 07:49:56 GMT

Hello engineers , im tryna test i2c with bmi270 to get the chip_id response . When read datasheet from Bosch it said that read_reg(0x00) to receive chip_id, so when testing in Logic analyzer can see that data 0x00 write to address 0x68 , then perform read at address 0x68 . But when debug with bmi270 cannot get the feed back chip_id. im using sda scl pull down.. Wonder if anyone has exprerience with this can check where's the problem , thanks a lot

volatile uint8_t chip_id = 0 ;
...
main(){

// Flexio_I2c_Ip_MasterSendData(0U, FLEXIO_I2C_CHANNEL_0, &reg, ONE_BYTE_SIZE, FALSE);

/* Wait master transfer to finish */
//while (((Flexio_I2c_Ip_MasterGetStatus(0U, FLEXIO_I2C_CHANNEL_0, NULL_PTR)) == FLEXIO_I2C_IP_BUSY_STATUS) && (timeout > 0))
//{
// timeout--;
//}

Flexio_I2c_Ip_MasterSendDataBlocking(
0, /* Instance */
0, /* Channel */
&reg, /* Tx buffer */
1, /* Size */
FALSE, /* SendStop = FALSE (IMPORTANT!) */
100 /* Timeout ms */
);

/* Send asynchronously from the master a read request to the slave device */
// Flexio_I2c_Ip_MasterReceiveData(0U, FLEXIO_I2C_CHANNEL_0, rxBufferMaster, TRANSFER_SIZE, TRUE);
// Flexio_I2c_Ip_MasterReceiveData(0U, FLEXIO_I2C_CHANNEL_0, &chip_id, 1, TRUE);

Flexio_I2c_Ip_MasterReceiveDataBlocking(
0, /* Instance */
0, /* Channel */
&chip_id, /* Rx buffer */
1, /* Size */
TRUE, /* SendStop = TRUE */
100 /* Timeout ms */
);

Re: S32K144 i2c bmi270 problem

PetrS — Tue, 16 Dec 2025 12:16:14 GMT

Hi,

the code used to read single register from slave looks correct
Flexio_I2c_Ip_MasterSendDataBlocking(0, 0, &reg, 1, FALSE, 100);
Flexio_I2c_Ip_MasterReceiveDataBlocking(0, 0, &chip_id, 1, FALSE, 100);

But from analyzer screenshot, it seems no byte is ACKed by slave.
So be sure SDA/SCL lines are properly pulled up and check the slave address is set as desired/configured on bmi270.

BR, Petr

Re: S32K144 i2c bmi270 problem

vinmotion — Tue, 16 Dec 2025 13:37:50 GMT

Hello Sir , i was able get the chip id i2c feedback from bmi but got problem when sending a large array in file example BLANK using flex io i2c as master, it send correct data array but some unknown 0x00 bytes at the end then stop, not execute the rest of program .

So i try to use lpi2c0 in file TEST as master with pin PTA2 and PTA3 but cannot receive data transmit in logic analyzer , Hope you can check the file zip TEST where could be wrong.... the whole point just to transmit a large array through I2c , const uint8_config_file[] = { ,

Re: S32K144 i2c bmi270 problem

PetrS — Wed, 17 Dec 2025 20:38:30 GMT

Hi,

in your TEST project you need to do below modifications:
- add INTC component, add I2C master interrupt and call respective API to init interrupts
- modify I2C timing to respect RM data
- use external pull ups on SDA/SCL, or enable internal weak pull ups at least

But without addressed slave connected a master sends just slave address and you got

BR, Petr

Re: S32K144 i2c bmi270 problem

vinmotion — Thu, 18 Dec 2025 03:23:25 GMT

Thank you for your support, have a great day Sir . Hopefully our company can move code project from stm32, teensy into NXP and use Nxp for mass productions.