CCS/TMS320F28069M: BaudRate

Ayushi Thakkar

Intellectual 840 points

Part Number: TMS320F28069M

Tool/software: Code Composer Studio

How can I adjust baudrate to 9600 and LSPCLK to 4MHZ?

I observe that I can divide SYSCLK to max by 14 , which gives me 90M/14 = 6.56 M HZ

If I consider this two conditions there is no way I can get my SPIBRR between 0 to 127.

Any idea on how to solve this ?

over 6 years ago

0 Mark Labbato over 6 years ago

Guru 30330 points

Ayushi,

Please confirm that you are trying to get the SPI to run at 9.6 kHz? this is extremely slow for SPI.
What device are are you trying to communicate with? 9600 sounds like a UART baud rate...

At 90MHz, there is no possible way to achieve 9.6 kHz.

-Mark

0 Ayushi Thakkar over 6 years ago in reply to Mark Labbato

Intellectual 840 points

yes , I was wrong about that.

Can you let me know how can I get 4MHZ for LSPCLK using SYSCLK, I can fix the same as baud rate.

0 Mark Labbato over 6 years ago in reply to Ayushi Thakkar

Guru 30330 points

Ayushi,

This is a pretty simple math problem that is well documented in the datasheet and TRM.
The Baud rate calculation for SPI is:
SPICLK = LSPCLK/(SPIBRR +1),

LSPCLK calculation is:
SYSCLK/LOSPCP

If you need 4MHz for LSPCLK, SYSCLK must be an even multiple of 4, with a maximum of 56MHz.

Again, Do you really need SPICLK to be so slow?

-Mark

C2000™︎ microcontrollers

C2000 microcontrollers forum

CCS/TMS320F28069M: BaudRate