LPUART not working after jumping from bootloader to application

[prasanna_v]

I have ported S32k148 Bootloader for S32k144 controller and i can load the application image from bootloader via LPUART1.

The sample application provided in S32DS for LED is working properly.

But when i try sample UART application (No SDK, No RTOS), it does not work properly (no output in serial console). The same application works properly when i boot from 0x0 address.

I verified whether the application image is flashed properly by reading the flash memory and everything seems to be fine. 

Not sure what is causing this issue. I tried to disable interrupts __asm("cpsid i"); before jumping to application but it did not help.

Any suggestions ?

[dianabatrlova]

Hello,

Since the bootloader and application are using LPUART1 and AN12218 jumping into the application without reset.

I suggest configuring another LPUART with related ports.

Pin muxing can be seen in the attachment of the RM rev 12.1 (S32K144_IO_Signal_Description_Input_Multiplexing.xlsx)

I hope it helps.

Best regards,

Diana

[prasanna_v]

Hi Diana,

Thanks for your reply.

We already have a custom board designed using S32k144 chipset. We have only one UART port connected to an external connector. So we don’t have any option to Use LPUART0 as debug port.

80	LPUART1_TX	I/O	PTC7/LPUART1_TX/CAN1_TX/FTM3_CH3/FTM1_QD_PHA/FTM1_QD_PHA/FTM3_CH3/LPUART1_TX/ADC1_SE5
81	LPUART1_RX	I	PTC6/LPUART1_RX/CAN1_RX/FTM3_CH2/FTM1_QD_PHB/LPUART1_RX/FTM1_QD_PHB/CAN1_RX/FTM3_CH2/ADC1_SE4

Basically we are using pin 80 & 81 which is PTC6 and PTC7 for UART port.

May I know the reason why the UART does not work in application if the same UART is already used In bootloader ?

Is there any other way to overcome this issue ?

Thanks,

Prasanna V

[dianabatrlova]

Hi Prasanna,

The reason is probably that you initialize the same ports and LPUART twice (in the bootloader and in the application). Also, these ports are already used by the java interface.

Reset MCU before jump into the application can be a possible solution.

I hope it helps.

Best regards,

Diana