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HAL Library seems to not follow classic programming guidelines

Question asked by Werner Dähn on Jun 9, 2018
Latest reply on Jun 17, 2018 by avi_crak.videocrak

I understand that programming enterprise software on a 8 core CPU with 4GHz and a simple STM32 MCU is different, nevertheless I would have added a few things to the HAL layer from the beginning:

 

  1. All HAL Init calls check if there is a collision with other resources. I configure PA1 as GPIO, then I use UART1 which needs PA1, hence the UART config should return an error. Granted, CubeMX is supposed to help you with that in a graphical manner but it does not in case you assign pins dynamically. And even if, what's wrong with validating that in a debug compile firmware a second time? Wouldn't that help beginners significantly?
  2. Programming a MCU is very hardware related. You need to open that gate to provide power to... by setting a register, switch the line to alternate pin by another register etc. From a HAL library I would expect to abstract exactly that. I want to enable UART1 on pin PA6, therefore the __HAL_RCC_GPIOA_CLK_ENABLE is called implicitly by the HAL_GPIO_Init function, the remap is called and the corresponding AF clock enabled and.... Things like that. Why should I remember every dependency if the HAL can do that for me?
    Another example: How many lines of code do you need to get an quadruple encoder (up/down counter) to work? Logically one call saying which pins to use and maybe choose the timer number. The counter specific X2 falling/X2 rising/X4 setting is needed also. Everything else can be derived from that information. Today you need 20-30 lines of code and if just one is wrong, you will not find out easily.
  3. The implementation is often too basic. Most obvious in the UART part of HAL. You can do char polling, add a interrupt callback or DMA. Fine. But useless as in most cases you would use a ring buffer. No rocket science but since when is that requested and yet still not available out of the box? Another missing receiver method is when timing plays a role like with serial packets. Every 20ms I get a packet that starts with 0x01 and ends with 0xEF and lasts for up to 5ms.

 

Wouldn't such things help greatly to get started? And to debug? And make the user experience better? And lower frustrations? And cause proper error messages rather than simply not working? 

 

Or am I missing something.

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