topic Re: No SCL/SDA Signals when using I2C Send as Master in S32K

No SCL/SDA Signals when using I2C Send as Master

phil_b — Tue, 15 Jul 2025 15:46:23 GMT

I have set up LPI2C1 as Master but get no outputs when attempting to send. I have pull-up resistors and the signals are connected to 1 slave device only. Please see below. What are some possible reasons for this problem?

Initialization:

/* set I2C1 interrupt */
IntCtrl_Ip_EnableIrq(LPI2C1_IRQn);
IntCtrl_Ip_InstallHandler(LPI2C1_IRQn, LPI2C1_Master_Slave_IRQHandler, NULL_PTR);

/* Init lpi2c in master mode */
Lpi2c_Ip_MasterInit(LPI2C_CHANNEL_0, &I2c_Lpi2cMasterChannel0);

Send data:

boolean I2C_read_fault_status(uint8 *rx_buffer)

{

TxBuff[0] = 0x78;

if (LPI2C_IP_SUCCESS_STATUS == Lpi2c_Ip_MasterSendData(LPI2C_CHANNEL_0, (uint8 *)&TxBuff[0], 1U, FALSE))

{

LM5171_data_ptr = rx_buffer;

LM5171_data_len = 1;

return TRUE;

}

Re: No SCL/SDA Signals when using I2C Send as Master

phil_b — Tue, 15 Jul 2025 20:37:48 GMT

The signals were missing while I was running in Debug mode. When I removed the debug connector, the signals were there! Is there a way to see the signals while in Debug mode?

Re: No SCL/SDA Signals when using I2C Send as Master

Senlent — Wed, 16 Jul 2025 06:23:47 GMT

Hi@phil_b

Could you tell us the part number you're using? Also, the RTD version is ?

If you're using S32K3, could you please try to set this bit and have a try again.

Re: No SCL/SDA Signals when using I2C Send as Master

db16122 — Wed, 16 Jul 2025 04:36:51 GMT

What kind of debug mode you are using? specific debugger or on board debugger?

Re: No SCL/SDA Signals when using I2C Send as Master

phil_b — Wed, 16 Jul 2025 13:28:16 GMT

We are using the S32K324 part with the S32DS3.5 debugger and a Multilink FX Universal interface. Our RTD version is 4.00 HF02. There is not an option in the LPI2C peripheral to enable debugging (like there is in other peripherals). I did not think to set the option manually! When I set the DBGEN bit, the signals work as expected.