RTOS/MSP432P4111: TI-RTOS SysTick Configuration

Mark Rodzinka

Expert 1105 points

Part Number: MSP432P4111

Tool/software: TI-RTOS

Here's my current configuration:

MSP432P4111 custom board
SimpleLink MSP432P4SDK 2.10.0.14
CCS V7.3.0
XDCTools 3.50.5.12
Compiler TI v17.9.0.STS

How do I configure the SysBios SysTick Interval for the MSP432, and which clock sources it?

I would ideally like to use the 128 KHz REF0 Clock mode to generate more accurate 1ms ticks (rather than using the 32768 mode).

However I'm unsure of how to do that in XCONF or the .cfg script.

My processor is running off of the 48MHz rate DCO.

I have set up the the REF0 for 128 KHz, and specified ACLK to be source by the 128KHZ REF0. However, my clock tick (SysTick) frequency appears to be based off of an assume ACLK of 32Khz rate.

I verified this by toggling a GPIO and doing a Task_sleep( 500 ) // 500 ticks. (I know this won't be 100 % accurate, but it should get me in the ballpark +/- 1 tick).

Instead of 500 ms, I get around a 125 Ms pulse width or roughly 1/4 the time, which is 32K / 128K = 1/4.

How do I tell SysBios the Tick is based off of the 128KHz rate instead of 32Khz?

over 5 years ago

0 Bob Landers over 5 years ago

TI__Expert 8510 points

Section 5.2 of the TI-RTOS Kernel user's guide provides instructions on how to adjust the clock module.

You might also refer to this post (which is 430 based) which shows how to change clock settings in the XDC .cfg file.

Note (for those reading this) that the .cfg file for SimpleLink SDK examples is in the associated TI-RTOS project NOT the application project.

-Bob L.

0 Mark Rodzinka over 5 years ago in reply to Bob Landers

Expert 1105 points

Thanks Bob.
I'm still a little confused as to what timer and clock is alloated to the SysTick event by default.

1) Is that by default TIMERA0?
2) Which clock source is the default (ACLK, MCLK, or SMCLK)?
3) Does the CPUFrequency field in XCONF correspond to the clock generating the sys tick (ie if SysBios uses ACLK, it would be 32K instead of the 48MHz DCO MCLK)?

My MCLK/CPU Clock is the 48MHz DCO, but that may not be appropriate for the CPU freq if SysBios is using the ACLK running at either 32K or 128K in my case

0 Bob Landers over 5 years ago in reply to Mark Rodzinka

TI__Expert 8510 points

TI-RTOS uses TimerA0 rather than the Cortex-M4 SysTick. ACLK is the default source clock. See this post for details on how to change this. I'll have to look up the CPU Frequency field to see what it does under the hood.

-Bob L.

0 ToddMullanix over 5 years ago in reply to Bob Landers

TI__Guru* 96960 points

Hi Mark,

You might want to look at this new page also: processors.wiki.ti.com/.../TI-RTOS_SimpleLink_Timers

Todd

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RTOS/MSP432P4111: TI-RTOS SysTick Configuration