Manual Clock Configuration Issue

[Len_Heske]

Hello,

first let me start this post by mentioning that I'm still very much a beginner.

I'm writing my own abstraction layer functions for the N657X0.

While running my clock_config() function, I ran into an issue that I don't know how to fix. The function works as follows:

- reset RCC->CR, CRGR1, CFGR2

- enable MSI and wait for MSI ready bit

- set CPU & SYS clock source to MSI and wait for clock source confirmation bits

- disable all other oscillators and all PLL

- reset RCC->HSICFGR

- configure HSI

- enable HSI and wait for HSI ready bit

- set CPU & SYS clock source to HSI and wait for clock source confirmation bits

- disable MSI

- reset RCC->MSICFGR

- configure MSI

- enable/disable oscillators (if HSIEN=0 then MSIEN=1 and vice-versa)

- reset RCC->ICxCFGR

- configure ICx

- reset RCC->PLLxCFGRx

- configure PLLx

- enable PLLx and wait for PLLx lock ready bit

- check CPU and SYS clock source selection

- check if source is actually active by checking the corresponding ready bit again

- select CPU and SYS clock sources (IC1 for CPU and IC2 for SYS)

- wait for clock source confirmation bits <- endless wait loop fault here!

The fault occurs at the very last link in the chain. I checked the clock source ready bit before when setting the sources to MSI/HSI and it worked then but not at the end. Is my clock_config() logic sound at all?

[mƎALLEm]

Hello,

As you are a beginner, I suggest you to use the HAL + CubeMx at the first time at least to inspire from the implementation.

PS: I'm not forcing you to use the HAL. I'm just suggesting you to accelerate the process, to understand the register configuration sequence and do some debug from your side.

[Len_Heske]

Hello @mƎALLEm,

thank you for your answer :)

Are you suggesting I should look at the HAL function code for inspiration? I should do that. Otherwise, I don't want to use HAL for my projects. I'm writing my own abstraction layer as a way to learn and as a hobby.

I'm using CubeMX only by looking at its clock config UI. The UI helps me understand how the oscillators and clock sources work. But I don't use CubeMX to setup my projects. I started with a bare bone main.c with nothing but the main function.

I'm wondering though, if you are seeing any glaring issue with my config logic? I'm not asking for help in regards to code fixing, just whether the overall logic is sound or not.

Thank you and kind regards,

Len

[mƎALLEm]

I was anticipating that reply from you and that's why I said:

"PS: I'm not forcing you to use the HAL. I'm just suggesting you to accelerate the process, to understand the register configuration sequence and do some debug from your side. "

I know you need to do it yourself but N6 is a complex product especially for beginners.  So what I suggest is to start with HAL and inspire from it. May be you find the answers there..

[Len_Heske]

Hello @mƎALLEm,

don't get me wrong, I totally understand this suggestion! What I'm doing is unnecessary and not the advisable thing to do as a beginner. I 100% agree with that notion.

I just do it as a hobby and it's not part of any serious workflow.

I'm sorry if my reply came across as cocky :)

Kind regards,

Len

[mƎALLEm]

---

@Len_Heske wrote:

I'm sorry if my reply came across as cocky :)

---

Don't worry.. I didn't feel targeted at all ;) . Just needed to clarify how to proceed..

[Danish1]

What values do you actually get in the clock source confirmation bits? And in other RCC registers?

Could you share your code? You describe yourself as a beginner. It is possible you've made a mistake e.g. in your bitwise operations looking for the confirmation bits

[TDK]

> The function works as follows: 

Why not show the function itself?

Only translation errors can be introduced by paraphrasing what it's doing.

[waclawek.jan]

I am not familiar with the 'Nx.

Are you running from FLASH? Do you set FLASH waitstates according to the system frequency?

Also, while others call for showing code, I'd recommend to read out and check/post content of relevant registers.

JW

[Len_Heske]

Hello @Danish1 and @TDK ,

thank you very much for your answers!

Should I send the entire code, i.e. my main.c and my library? Or just the function in question? I work with a lot of structs, so I'm concerned about the readability of it.

I attached a file with the function in question and some comments. I have no idea what a good code should look like so I'm sorry if it's ugly :D

Btw, this is the definition of the clear() function if you think it could be the culprit:

void clear(volatile uint32_t*reg, unsigned bit, unsigned pos)

{

    *reg &= ~(((high<<bit)-high)<<pos);

}

Kind regards,

Len