CCS/TDA2EXEVM: How to set the clock input frequency (SYS_CLK1) 27 MHz for timer3.

kiran vidhate

Part Number: TDA2EXEVM

Tool/software: Code Composer Studio

Hi,

I am trying set the input frequency(SYS_CLK1) 27 MHz for Timer 3 ,but it has not changed.For 27 MHz , I have made below setting on Evaluation board.

GPMC_AD8 (sysboot8) GPMC_D08 SW4.P1-OFF
GPMC_AD9 (sysboot9) GPMC_D09 SW4.P2 -ON

After this setting when we check the address 0x4A00 26C4 -CTRL_CORE_BOOTSTRAP in debug at that time we saw the pin 9 was set.

also set the 0x4AE0 6110-CM_CLKSEL_SYS for 27 MHZ. But frequency has not changed for 27 MHz.

according to the

32.2.4.2 System Clock Speed Selection

There are three crystal speeds available to be selected by means of sysboot[9:8], as described in
Table 32-7. User is responsible to set the correct value depending on the actual clock supplied to the
device.
Table 32-7. System Clock (SYS_CLK1) Speed Selection
sysboot[9:8] SYS_CLK1 Speed
0b00 Reserved
0b01 20 MHz
0b10 27 MHz
0b11 19.2 MHz

Please suggest ,how to configure timer 3 for 27 MHz.

Regards,

Kiran Vidhate

over 8 years ago

0 Stanislav Stilyanov over 8 years ago

TI__Mastermind 25170 points

Hi Kiran,
The below quote should answer your question:
"User is responsible to set the correct value depending on the actual clock supplied to the device."

That is, your first and most important step is to supply a faster (27 MHz) clock (external or crystal) and only then tell the SoC you are supplying 27 MHz (in fact two steps must be done during power off).
Now you are only telling the SoC, but not feeding any different (i.e. 27 MHz) clock.

Also, I hope you understand that SYS_CLK1 is the main clock for the SoC, not only timer clock.

Regards,
Stan

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CCS/TDA2EXEVM: How to set the clock input frequency (SYS_CLK1) 27 MHz for timer3.