c5515 Clock Stop Requests

Mike241

I am trying to follow the procedure to perform a clock stop when I am setting the EBSR to use a UART. The problem is that my stop request placed in the URTCLKSTPREQ field of the CLKSTOP register is not being acknowledged unless the receive line is high.

Is there a step that I can skip in setting up EBSR so that my setup procedure doesn't hang waiting for an acknowledgement? For example, if I know I am not using the UART, can I skip the REQ step and go straight to clock gating of UARTCG in PCGCR1?

Is the purpose of the REQ/ACK process to avoid interrupting a transaction or is there another reason, such as protecting the circuitry?

over 14 years ago

0 Steve Tsang over 14 years ago

TI__Mastermind 23785 points

Yes. You can set the peripheral clock gating control register at 0x1C02 before setting EBSR at 0x1C00.

Regards.

0 Mike241 over 14 years ago in reply to Steve Tsang

Intellectual 620 points

Thanks, Steve.

Can I also set PCGCR without having to set and wait for CLKSTOP (0x1C3A)?

0 Steve Tsang over 14 years ago in reply to Mike241

TI__Mastermind 23785 points

The CLKSTOP is intent to use for Request/Acknowledge handshake. It is always good to wait for this protocol is complete before turnoff the clock. Only in the case of right after a reset,, when you are sure that there is no active peripheral transaction is occurring, then you might skip the handshake. User need to exercise judgemenet what is right for their application.

Regards.

0 Mike241 over 14 years ago in reply to Steve Tsang

Intellectual 620 points

Yes, I am doing this directly after reset when I know nothing is happening on the peripheral, but wanted to make sure no damage to the peripheral would occur if I stop the clock without the ACK being received.

Thank you for your help on this.

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c5515 Clock Stop Requests