How to modify UART2 for special baudrate??? (linux SDK6.0)

justin wang1

Expert 1085 points

Other Parts Discussed in Thread: AM3352

I use AM3352 TI SDK6.0,and the UART2 able to communications with PC at 115200 bps

but,i want to use the baudrate 937kbps for communications with other device (DSP c2000)

how to modify UART2 baudrate to 937Kbps??

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Hi Justin,

You will not be able to achieve 837kbps exact baud rate with the AM335X UART. See section 19.3.8.1.2 in the AM335X TRM Rev. L for details on baud rate calculation.

0 justin wang1 over 10 years ago in reply to Biser Gatchev-XID

Expert 1085 points

Thanks Biser,

If I change to Other Baudrate, Will the other UART be affected??

If I want to change UART_DLH,DLL,which file need to be modified in kernel3.2?

0 Biser Gatchev-XID over 10 years ago in reply to justin wang1

TI__Guru**** 393215 points

I have asked the SW team to provide this information. It will be posted here.

0 justin wang1 over 10 years ago in reply to Biser Gatchev-XID

Expert 1085 points

Thanks Biser,

I found the same baudrate with DSP C2000 in 375kBPS

how to modify the kernel3.2 for UART2 375k

0 Georgi Karpov over 10 years ago in reply to justin wang1

Expert 1185 points

Hi Justin,

you can change UART_DLH,DLL by changing values on respective addresses.
Please refer to 2.1 "ARM Cortex-A8 Memory Map" in AM335X TRM to find UARTi address.
Follow steps in 19.4.1.1.3 "Protocol, Baud Rate, and Interrupt Settings" to configure baud rates.

BR,
Georgi

0 justin wang1 over 10 years ago in reply to Georgi Karpov

Expert 1085 points

Thanks Georgi

I use "linux kernel 3.2"

I should modify the linux driver, right??

please tell me which file in kernel for AM335X UART2

0 justin wang1 over 10 years ago in reply to justin wang1

Expert 1085 points

I found a solution as following,only modify the omap-serial.c

now my uart2 can send correct 375k baudrate

Thank lot~

0 Georgi Karpov over 10 years ago in reply to justin wang1

Expert 1185 points

Look into
./linux-3.2/drivers/tty/serial/omap-serial.c
There is a function serial_omap_set_termios() that is used to configure uart ports.

BR,
Georgi

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How to modify UART2 for special baudrate??? (linux SDK6.0)