AM5728: PWMSS1 clock frequency

Sylvain PALMERI

Part Number: AM5728
Other Parts Discussed in Thread: TMS320F2812,

Hello,

I use the PWMSS1 module as eCAP. The counter ECAP_TSCNT is running and an ISR is generated on a rising edge of the input signal. when this event occurs, the CAP1 register is caught and reset the counter, so that I can calculate the period of the input signal with the following formula:

Period = CAP1(deci) x (1/SYSCLKOUT) .

The problem is that I don't know where to find the value of SYSCLKOUT. In the TMS320F2812 or F28335, the SYSCLKOUT is 150MHz. In the AM5728 it seems that the value is 100MHz (but I'm not sure, its not very clear in the TRM). When I use 100MHz in my calculation, I have a big error between the period mesured with an oscilloscope and the period calculated (9.32ms measured for 12.5ms calculated). The good value estimated following the measured period should be around 133MHz.

Also, with the Clock Tree tool, the clock source of the PWMSS1 module is L4PER2_L3_GICLK that is cadenced at 10MHz... I can't find the relation in the TRM between L4PER2_L3_GICLK and SYSCLKOUT.

Could you tell me where I can get the good information?

Regards,

Sylvain.

over 5 years ago

0 Brad Griffis over 5 years ago

TI__Guru*** 125430 points

Sylvain PALMERI said:
Also, with the Clock Tree tool, the clock source of the PWMSS1 module is L4PER2_L3_GICLK that is cadenced at 10MHz... I can't find the relation in the TRM between L4PER2_L3_GICLK and SYSCLKOUT.

I dumped the *.rd1 from my board running Linux. I imported that rd1 into Clock Tree Tool and it showed PWMSS1 having an input clock of 133 MHz.

0 Sylvain PALMERI over 5 years ago in reply to Brad Griffis

Expert 1145 points

Hi brad,

That's exactly what I expect when I calculate it from the measured period !

I'm not really familar with the Clock Tree Tool. Could you please tell me how to get the 133MHz clock info?

Regards,

Sylvain.

0 Brad Griffis over 5 years ago in reply to Sylvain PALMERI

TI__Guru*** 125430 points

Are you using Linux? If so, please refer to CTT_USER_MANUAL.pdf, Section 5.4.4.1.2 OMAPconf Memory Dump under Linux. It is in the Docs directory of Clock Tree Tool (CTT).

Alternatively it can be done via JTAG using the following script:

http://git-stage.itg.ti.com/sitara-dss-files/am57xx-dss-files/blobs/raw/master/am57xx-ctt.dss

Directions on how to use the script are available here:

http://git-stage.itg.ti.com/sitara-dss-files/am57xx-dss-files/blobs/master/README

Best regards,
Brad

0 Sylvain PALMERI over 5 years ago in reply to Brad Griffis

Expert 1145 points

For the moment, I use the DSP core only, in baremetal. The ARM, that will run under Linux RT, is not implemented yet.

I tried the links but can't connect. It returns an error

Anyway, I found another post where you give other (active) link that should be identical.

http://git.ti.com/sitara-dss-files/am57xx-dss-files/blobs/master/README

http://git.ti.com/sitara-dss-files/am57xx-dss-files/blobs/raw/master/am57xx-boot.dss

I guess that this script generates the rd file that you mention previously, but do you have any documentation how to use it in the clock tree tool?

Regards,

Sylvain.

0 Sylvain PALMERI over 5 years ago in reply to Sylvain PALMERI

Expert 1145 points

Hi Brad,

The script worked as expected. I got the 133MHz appears in the clock tree. Thanks a lot.

Actually I don't know exactly how I get these configured registers resulting the script, because I run the script just after power up the board, without any software executed, and without any clock registers initialization.

Does the generated file show default registers following reset state?

Regards,

Sylvain?

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AM5728: PWMSS1 clock frequency