I'm running I3C on LPC55S36-EVK and find out that it cannot be read more than 16 bytes.
This issue can be reproduced in Building an I3C Sensor Network Using LPC553x/LPC55S3x example. After initialization of the icm42688p is complete, reading 17 bytes from the icm42688p sensor causes I3C_ReadSensor to hang. And we can see that SDA will be pulled down forever.
if (demo_icm42688pDev != NULL ) {
// ...
result = ICM42688P_Init(&icmp42688p_handle, &icm42688p_sensorConfig);
if (result != kStatus_Success)
{
PRINTF("\r\nSensor reset failed.\r\n");
return -1;
}
// ...
uint8_t bankSel = 0;
/* Select bank 0 to read sensor data.*/
result = ICM42688P_WriteReg(&icmp42688p_handle, BANK_SEL, &bankSel, 1);
if (result != kStatus_Success)
{
PRINTF("\r\nSelect sensor bank 0 failure.\r\n");
return -1;
}
// test
SDK_DelayAtLeastUs(1000 * 1000, SystemCoreClock);
static uint8_t buffer[256];
I3C_ReadSensor(demo_icm42688pDev, 0x00, buffer, 17);
}
Note
1. If the length of reading is less or equal to 16 bytes, there is no problem.
2. I am assuming that this is not a problem with the icm42688p as I get the same problem with an another sensor.
Environment
Platform: LPC55S36-EVK
SDK: Build SDK for LPCXpresso55S36 2.16.000 (released 2024-07-12)
Sample: Building an I3C Sensor Network Using LPC553x/LPC55S3x
Hi @bell_huang
I tested the lpcxpresso55s36_i3c_master_read_sensor_icm42688p example.
And i reproduce the issue that you mentioned.
I have tracked this function.
The parameter handle ->remaining bytes is finally passed into the read function.
Therefore, it is believed that the sensor can only return a maximum of 16 bytes of data.
BR
Hang
Hi @Harry_Zhang ,
Thanks for responses.
I think this is a problem caused by the LPC55S366 for the following three reasons:
1. There are similar conditions for other sensors besides icm42688p, and they don't necessarily occur at the case of more than 16 bytes.
2. In addition to the SDA possibly being pulled out, the SCL may also be pulled out. There is no reason that any sensor should be designed to control SCL.
3. I moved the same sensor to another MCU platform that supports I3C and this problem does not occur.
This problem can also be reproduced using the NXP p3t1175 temperature sensor. After initialization of the p3t1175 is complete, reading 23 bytes from the p3t1175 sensor causes I3C_ReadSensor to hang. And we can see that SCL will be pulled down forever.
if (demo_p3t1175Dev != NULL ) {
//...
result = P3T1175_Init(&p3t1175_handle, &p3t1175_sensorConfig);
if (result != kStatus_Success)
{
PRINTF("\r\nTemp Sensor reset failed.\r\n");
return -1;
}
//
// readLength = 22, no problem
// readLength = 23, SCL or SDA be pulled low
//
size_t readLength = 23;
SDK_DelayAtLeastUs(1000 * 1000, SystemCoreClock);
static uint8_t buffer[256];
I3C_ReadSensor(demo_p3t1175Dev, 0x00, buffer, readLength);
}
PRINTF("Finished\r\n");
while (true);
However, I tested the p3t1175 on an another I3C supported platform and had no problem reading 100 bytes.
