topic Re: LPC1114 strange behaviour while reading LPC_SYSCTL->PDRUNCFG in LPC Microcontrollers

LPC1114 strange behaviour while reading LPC_SYSCTL->PDRUNCFG

bjoern_harre — Thu, 10 Oct 2024 19:43:59 GMT

I don't understand why the program counter JUMPS. Only the register shall be read. If I would change R2 into 0x0000 0034 manually, the behaviour is ok.

Re: LPC1114 strange behaviour while reading LPC_SYSCTL->PDRUNCFG

xiangjun_rong — Fri, 11 Oct 2024 03:00:51 GMT

Hi,

When a module is powered off, it can not be read. If you access the registers of module, you must power the module.

Hope it can help you

XiangJun Rong

Re: LPC1114 strange behaviour while reading LPC_SYSCTL->PDRUNCFG

bjoern_harre — Fri, 11 Oct 2024 06:09:14 GMT

I understand what you mean. But this register LPC_SYSCTL->PDRUNCFG is powered. I can edit it with the debugger.

Re: LPC1114 strange behaviour while reading LPC_SYSCTL->PDRUNCFG

xiangjun_rong — Fri, 11 Oct 2024 09:22:06 GMT

Hi,

could you clarify your question so that I can understand your issue clearly?

Xiangjun Rong

Re: LPC1114 strange behaviour while reading LPC_SYSCTL->PDRUNCFG

bjoern_harre — Fri, 11 Oct 2024 09:35:28 GMT

What flag do I have to set or clear in any register to get access to this LPC_SYSCTL->PDRUNCFG?

Re: LPC1114 strange behaviour while reading LPC_SYSCTL->PDRUNCFG

xiangjun_rong — Fri, 11 Oct 2024 09:57:46 GMT

Hi,

You can access all the register in SYSCON module without any condition, for your case, you can access the SYSCON->PDRUNCFG0 directly without any restriction.

But for exampler if you access the ADC0 register, you have to enable gated clock for ADC0

set AHBCLKCTRL0[ADC0] bit

If you want to ADC work, you have to do:

set the ADC power by configuring the PDRUNCFG0

configure the correct ADC clock with ADCCLKDIV reg and ADCCLKSEL reg.

Hope it can help you

XiangJun Rong

Re: LPC1114 strange behaviour while reading LPC_SYSCTL->PDRUNCFG

bjoern_harre — Fri, 11 Oct 2024 10:25:49 GMT

That is the strange behaviour. If you look at my video you can see at the disassembler site that the register LPC_SYSCTL->PDRUNCFG shall be load in a register. And in that step something strange happenes. The question is, why?