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Graduate II
September 8, 2025
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What is "hal_ppp"?

  • September 8, 2025
  • 2 replies
  • 526 views

Hi, 

This might seem like a dumb comment, but I am reading UM1884, Description of STM32L4/L4+ HAL and low-layer drivers, and I find numerous references to "hal_ppp" or "HAL_PPP" such as the file name "stm32l4xx_hal_ppp.c" (Table 2, page 8) or "HAL_PPP_STATE_RESET" (P2566).

When grepping the generated file structure, I also find a few references to "HAL_PPP" or "hal_ppp" peppered around a few header and c source comments but no actual functional code.

So, I think, perhaps, that "HAL_PPP" is a placeholder for peripheral modules such as "HAL_RTC..." or "HAL_PWR..." peripheral names.

My bone to pick is this:  that "hal_ppp" or "HAL_PPP" are placeholders is NOT stated anywhere in the documentation.  You have to assume that is the case.  Sorry, but I am a literal thinker and the lack of an explanation about the meaning of "ppp" or "PPP" is a cause of concern, distraction, annoyance and doubt, so much so that I was compelled to write this.

Please, to the document authors, do not introduce placeholders or assumed names without explaining what these are.

Regards,
Allan

 

    This topic has been closed for replies.
    Best answer by Saket_Om

    Hello @AMacd.1 

    This acronym 'PPP' is described in the UM1884 at the page 5.

    Saket_Om_0-1758207888070.png

     

     

     

    2 replies

    Technical Moderator
    September 8, 2025

    Hello @AMacd.1 

    IN UM1884, the terms HAL_PPP, hal_ppp, and similar references (e.g., stm32l4xx_hal_ppp.c, HAL_PPP_STATE_RESET) are used as generic placeholders for actual peripheral names. The acronym PPP stands for "peripheral" and is intended to be replaced by the specific module you are working with, such as UART, I2C, SPI, RTC, or PWR. For example, HAL_PPP_Init() would correspond to HAL_UART_Init() for the UART peripheral, and stm32l4xx_hal_ppp.c would become stm32l4xx_hal_uart.c. This convention is used throughout ST’s documentation, code templates, and comments to avoid redundancy and to provide a unified description for all peripherals.

    THX

    Ghofrane

    Saket_OmAnswer
    Technical Moderator
    September 18, 2025

    Hello @AMacd.1 

    This acronym 'PPP' is described in the UM1884 at the page 5.

    Saket_Om_0-1758207888070.png