TMS570LS3137: PCNT in N2HET

sreenivasan m

Part Number: TMS570LS3137

Hi,

This is regarding the continuation of previous case. We need to detect whether the input signal frequency is present or not from N2HET module.
Also, can you tell me the min and max frequency that N2HET measures?

Regards,
M.Sreenivasan.

over 7 years ago

0 sreenivasan m over 7 years ago

Genius 3705 points

Hi Team,
Any inputs on this?

0 Sunil Oak over 7 years ago

TI__Mastermind 49120 points

Hello,

The datasheet specifies the N2HET input timing requirements. Please see www.ti.com/.../peripheral_information_and_electrical_specifications

The max frequency input depends on the actual timer channel being used.

Regards,
Sunil

0 karthick ganeshan over 7 years ago in reply to Sunil Oak

Prodigy 250 points

hi Sunil, thanks for the update. I was able to ressove this issue... I would appreciate if you can help me with the bootloader issue asap .... thanks

0 sreenivasan m over 7 years ago in reply to Sunil Oak

Genius 3705 points

Hi Sunil,

I was referring to the below problem:
We are using PCNT instruction to count the number of pulses using N2HET module. We tried giving input signal frequency and could see the number of pulse count. After that, when we give no input signal, it still shows the previous captured value.
Is there any way to detect whether input signal is present or not through N2HET module?

Regards,
M.Sreenivasan.

0 Sunil Oak over 7 years ago in reply to sreenivasan m

TI__Mastermind 49120 points

Hi Sreenivasan,

Are you enabling the auto read clear feature of the PCNT instruction? See section 20.2.4.3 on page 778 of SPNU499B. This allows the data field of the selected instruction to be cleared to zeros after a read by the CPU (or HTU). This way you can also identify if a new pulse has been received.

Regards,
Sunil

0 sreenivasan m over 7 years ago in reply to Sunil Oak

Genius 3705 points

Hi Sunil,

We are trying to calculate the number of pulses measured in a given period and we are able to read the value correctly for the given input. But, after running CCS continuously for sometime, could see that number of pulses measured is zero. But, with breakpoints, if we run, we could see its value. Even we verified it in memory, but still its value is not getting changed when we run CCS in continuous mode. Can you please show some light into this behaviour?

We are using CCS8.0

Regards,
M.Sreenivasan.

0 sreenivasan m over 7 years ago in reply to sreenivasan m

Genius 3705 points

Attaching the snapshot, please see the highlighed one, once it reaches to 0x01FFFFFF, we are not able to read pulse period when CCS is in continuous run mode.

0 sreenivasan m over 7 years ago in reply to sreenivasan m

Genius 3705 points

Hi Sunil,

Any updates or any info required, please let me know.

Regards,
M.Sreenivasan.

0 sreenivasan m over 7 years ago in reply to sreenivasan m

Genius 3705 points

Hi Sunil ,

I just tested that with control field not set ON, HET module is able to capture the number of pulses measured is not zero. Do you see any limitations for setting the control field under ON case?
A quick response is highly appreciated.

Regards,
M.Sreenivasan.

0 Sunil Oak over 7 years ago in reply to sreenivasan m

TI__Mastermind 49120 points

The "Control" bit only affects the value of the immediate data field of the PCNT instruction on a CPU read. The application just needs to be aware of this when reading the data field. There are no other limitations associated with this bit.

Regards,
Sunil

0 sreenivasan m over 7 years ago in reply to Sunil Oak

Genius 3705 points

Hi Sunil,
Yes you are correct, but we are calculating the pulses. So, we are clearing the data field in ADD instruction.
Even we tried to clear the Data field after reading its value from software (with control is not set to ON). Still the behaviour is same.
It would be good, if we can have a short call, you can send meeting notification to my registered mail id.

Regards,
M.Sreenivasan.

0 sreenivasan m over 7 years ago in reply to sreenivasan m

Genius 3705 points

Any updates on this?

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TMS570LS3137: PCNT in N2HET