IMX8MP: System crash while writing BRM value to set Serial baud rate

[Saqib]

I am trying to write serial driver for i.MX 8M Plus EVK cortex M7 core. system crashes when I try to write BRM value to set the serial baud rate.

I have a few questions now:

This block diagram shows that we need two clocks for serial.

1) How can we ensure that the module clock is enabled. I have gone through the clocks chapter but didn't find out what exactly is module clock is for Uart4.

2) what can we expect if the module clock is disabled and we try to write BRM register to set serial baud rate? A system crash?  

3) Is there any separate document by NXP that briefly explains UART architecture and programming?

[igorpadykov]

Hi Saqib

>1) How can we ensure that the module clock is enabled. I have gone through the clocks chapter

>but didn't find out what exactly is module clock is for Uart4.

one can check CCGR76 register, Table 5-9. CCGR Mapping Table,
also description can be found in sect.5.1.6.3 CCGR Interface, Table 5-1. Clock Root Table

(UART4_CLK_ROOT)  i.MX 8M Plus Applications Processor Reference Manual

>2) what can we expect if the module clock is disabled and we try to write BRM register

>to set serial baud rate? A system crash?

yes

>3) Is there any separate document by NXP that briefly explains UART architecture and programming?

no.

Best regards
igor