How to port to different MCU

[iammmmmmm]

I'm currently trying to port GrblHAL to two microcontrollers: the APM32F103VCT6 (featuring 256KiB Flash, 64KiB SRAM, 96MHz) and the APM32F407VGT6 (with 1MiB Flash, 192KiB SRAM, 4KiB Backup SRAM, 168MHz). These chips offer a rich set of peripherals, powerful performance, and, most importantly, they are extremely cost-effective (e.g., the APM32F407VGT6 is available for as low as 12 RMB on JLC).

Despite having spent about four to five hours reviewing GrblHAL-related content and scouring the internet, including (but not limited to) the following resources:

#318
https://github.com/grblHAL/Templates/tree/master/arm-driver
https://github.com/grblHAL/core/wiki/Hardware-Abstraction-Layer-(HAL)----developer-reference

I still find myself completely at a loss. I haven't been able to find any clear guidance on how to port GrblHAL on Google, and I don't know where to begin. Simply cloning an existing STM32XX implementation would only make me more confused and directionless.

I'm desperately looking for:

• Clear tutorials or guides that specifically walk through the GrblHAL porting process.
• Or, is there an interface and implementation specification (an "API") similar to TinyPrintf, that clearly defines which methods need to be implemented to meet specific requirements? Like TinyPrintf, where I just implement a io_putchar function and pass it during init_printf initialization, and then I can use it freely:

init_printf，之后就能随意使用了：

void io_putchar(void *p, char ch) {
  USART_TxData8(DEBUG_USART, ch);
  uint32_t timeout = USART_TIMEOUT;
  while (USART_ReadStatusFlag(DEBUG_USART, USART_FLAG_TXBE) == RESET && timeout--);
}

 init_printf(0, io_putcharB);

Any help would be greatly appreciated! Please excuse my English, which may not be perfect. Should there be any ambiguity or questions in the English phrasing, please kindly refer to my original Chinese text for clarification.

我正尝试将 GrblHAL 移植到apm32F103VCT6（有256KiB Flash 64KiB SRAM 96MHz 主频）和apm32F407VGT6（有1MiB Flash 192KiB SRAM 4KiB备份 168MHz 主频）这两款微控制器上。这些芯片不仅外设丰富、性能强劲，更重要的是它们价格低廉（例如 APM32F407VGT6 在嘉立创最低仅售 12 元人民币）。
尽管我已经花费了四五个小时查阅 GrblHAL 相关资料并搜索互联网，包括但不限于：

#318
https://github.com/grblHAL/Templates/tree/master/arm-driver
https://github.com/grblHAL/core/wiki/Hardware-Abstraction-Layer-(HAL)----developer-reference

请原谅我都平庸无能，我在谷歌上找不到任何明确的指导如何移植grbl hal 的结果，我不知道从哪里开始，去克隆某个已经实现的stm32xx的实现并开始只会让我更加混乱找不到方向。

我依然感到非常困惑。我在谷歌上找不到任何明确的 GrblHAL 移植指南，也不知道从何开始。直接克隆一个已有的 STM32XX 实现只会让我更加迷茫，找不到方向。

我急切地想知道：

• 是否有清晰的教程或指南来指导 GrblHAL 的移植工作？
• 或者是否存在类似于 TinyPrintf 那样的接口和实现规范（“API”），能明确告诉我具体需要实现哪些方法以符合要求？就像 TinyPrintf 那样，我只需实现一个 io_putchar 函数，然后在初始化时将其传递给 init_printf，之后就能随意使用了：

void io_putchar(void *p, char ch) {
  USART_TxData8(DEBUG_USART, ch);
  uint32_t timeout = USART_TIMEOUT;
  while (USART_ReadStatusFlag(DEBUG_USART, USART_FLAG_TXBE) == RESET && timeout--);
}

 init_printf(0, io_putcharB);

对于任何帮助，我将不胜感激！请原谅我的英语可能不尽完美，如果英文表述中存在任何歧义或疑问，请以我的中文原文为准。

[terjeio]

This comment may help a little bit.

Clear tutorials or guides that specifically walk through the GrblHAL porting process.

I have not written any that is remotely up to date. It would be nice if someone who create a new port would document the process.
As stated in the above comment the best option would be to start with an existing one, likely the STM32F1xx driver in your case, comment out all code that fails to compile and then work on bringing up the MCU (clock tree setup, in main.c) and serial comms over UART (serial.c). Then add back required functionality.

Or, is there an interface and implementation specification (an "API") similar to TinyPrintf, that clearly defines which methods need to be implemented to meet specific requirements?

Kind of - the HAL functions, some of which are optional. grblHAL is in large parts "bare metal" and only relies upon external libraries for the more advanced functionality like USB and network communication.

[iammmmmmm]

Thanks for your answer, I will try it
谢谢您的回答，我会尝试的。

[iammmmmmm]

我下载了适用于 STM32F3xx 的 grblHAL 固件源代码进行研究。在阅读驱动层代码时，我注意到其中频繁使用了 C 标准库函数。以我个人的经验和理解，在微控制器（MCU）项目中，过度依赖标准库函数可能并非最佳实践。

我的主要顾虑在于：标准库函数通常为了实现其广泛的通用性和兼容性，会包含大量在 MCU 环境下不必要的复杂代码和抽象层。这不仅可能导致编译后的固件体积显著膨胀（例如增加几十 KiB），对于资源受限的 MCU 来说，这种额外的开销在内存和性能方面都显得性价比不高。因此，在我的单片机开发实践中，我通常会选择手动实现所需的精简功能，或者寻找专为 MCU 优化设计的替代库（例如 tinyprintf 这样的轻量级 printf 实现）。

这仅仅是我个人在嵌入式开发中的一点看法。我想请教一下，如果不使用这些 C 标准库函数，会对项目造成负面影响吗？或者说，在 grblHAL 这样的项目中，使用标准库函数是否反而是一种更好的选择呢？我很希望能了解这背后的考量。

I downloaded the grblHAL firmware source code for STM32F3xx to study. While reading the driver layer code, I noticed that C standard library functions were frequently used. In my personal experience and understanding, over-reliance on standard library functions may not be the best practice in microcontroller (MCU) projects.

My main concern is that standard library functions usually contain a lot of complex code and abstraction layers that are unnecessary in the MCU environment in order to achieve their wide versatility and compatibility. Not only can this cause the compiled firmware to be significantly larger (for example, tens of KiB more), but for resource-constrained MCUs, this additional overhead is not cost-effective in terms of memory and performance. Therefore, in my MCU development practice, I usually choose to manually implement the required streamlined functions or look for alternative libraries that are optimized for MCUs (such as lightweight printf implementations such as tinyprintf).

This is just my personal opinion in embedded development. I would like to ask if not using these C standard library functions will have a negative impact on the project? Or, in a project like grblHAL, is using standard library functions a better choice? I really hope to understand the considerations behind this.