AM6442: Do AM64 support PTO function?

Hello Zekun

Thank you for the query.

Are you checking if there is availability of demo similar to the one you attached or checking on the feasibility.

The PRU-ICSSG capabilities are available on the AM644x.

As i understand we have not done any prototyping or testing of PTO.

Regards,

Sreenivasa

Hi, Sreenivasa

So from PRU perspective, it support PTO, but we just don't have demo.

Is it one PRU-ICSSG support one PTO channel?

Regards

Zekun

Hello Zekun

Thank you.

I would expect it to be similar to the AM335x.

Regards,

Sreenivasa

Hi Sreenivasa

But I don't quiet for sure if PRU-ICSS support one channel on AM335 or AM64. Could you help to check this because customer cares more about this. Thanks

What is the difference between PTO or PWM? Is it the same thing?

Regards

Zekun

Hello Zekun

Thank you.

Looks like the Am335x TI design was done by the SEM team.

Let me check or assign to the SEM team to provide their inputs.

Please expect some delay.

Regards,

Sreenivasa

Hi Zekun,

  PTO implementation from AM335x can also run on AM64x. It takes one PRU core. AM64 has 12 PRU cores. If you do not use PRU-ICSS_G for other functions you can do 12 channels.

- Thomas

Hi， Thomas

Thanks for help.

More questions here.

1. One PRU core pair to one PTO function, but if we want to use PRU-ICSS_G to achieve function like ETH, PWM output, or connect with external encoder, can the PTO channel be affected?

2. Do AM64 already have PTO firmware and driver? Do customer need extra work to enable PTO on AM64, or just use it like AM335 ?

Thanks

Regards

Zekun

Hi Zekun,

  yes you can map multiple functions on 12 PRU cores.

For example,

- ICSS_G1: PRU0/1 EtherCAT

- ICSS_G1: TX_PRU0 MDIO emulation

- ICSS_G1: RTU0/1 TX_PRU1 available

- ICSS_G0: PRU0 - sigma delta current sense - 3 channel

- ICSS_G0: PRU1 - Tamagawa Encoder

- ICSS_G0: RTU1 - 2nd Encoder

- ICSS_G0: RTU0, TX_PRU0 and TX_PRU1 available

In above mapping you have 6 PRUs available to implement PTO. 

AM64 does not have PTO driver in SDK. Customer would need to port the AM335x example. However the PRU GPIO mode is already taken by EtherCAT, encoder and current sense. Instead of using PRU GPO I would program EDIO which are also low latency for PRU.

- Thomas

Hi, Thomas

Thanks for your detailed explanation.

So based on your example, if we add PRU_UART as well, what is the maximum of PRU_UART we can get if we add 2 PTO?

- ICSS_G1: PRU0 -  EtherCAT

- ICSS_G1: PRU1 - PTO

- ICSS_G1: RTU0  - PRU_UART

- ICSS_G1: RTU1 - PTO 

- ICSS_G1: TX_PRU0 MDIO emulation

- ICSS_G1: TX_PRU1 - PRU_UART

- ICSS_G0: PRU0 - sigma delta current sense - 3 channel

- ICSS_G0: PRU1 - Tamagawa Encoder

- ICSS_G0: RTU0 - 2nd Encoder

- ICSS_G0: RTU1  - PRU_UART

- ICSS_G0: TX_PRU0 - PRU_UART

- ICSS_G0: TX_PRU1  - PRU_UART

Regards

Zekun