2026-01-08 2:54 AM - last edited on 2026-01-08 3:28 AM by Andrew Neil
Hi everyone,
I am working on a project with the NUCLEO-H7S3L8 and trying to read 2 ADCs simultaneously in Continuous Conversion mode using HPDMA.
The Goal:
ADC1 & ADC2: Reading 7 channels each (14 channels total).
Mode: Continuous Conversion, Circular Mode.
Transfer: HPDMA to SRAM (AHB SRAM).
The Problem: I am receiving data, but the values are extremely unstable/fluctuating.
When running a smaller example from a ST-Employee, values were stable (around 400).
With the full 7-channel scan, the data fluctuates significantly, at a level where data should be wrong.
Can someone take a look at it? They both use the same bootloader. I honestly cant see any issues with my custom config.
Thanks in advance.
This is also my linker if relevant:
/*
******************************************************************************
**
** @file : LinkerScript.ld
**
** @author : STM32CubeIDE
**
** Abstract : Linker script for STM32H7Sxx Device
** 128KBytes FLASH
** 456KBytes RAM
**
** Set heap size, stack size and stack location according
** to application requirements.
**
** Set memory bank area and size if external memory is used
**
** Target : STMicroelectronics STM32
**
** Distribution: The file is distributed as is, without any warranty
** of any kind.
**
******************************************************************************
** @attention
**
** Copyright (c) 2024 STMicroelectronics.
** All rights reserved.
**
** This software is licensed under terms that can be found in the LICENSE file
** in the root directory of this software component.
** If no LICENSE file comes with this software, it is provided AS-IS.
**
******************************************************************************
*/
/* Entry Point */
ENTRY(Reset_Handler)
/* Highest address of the user mode stack */
_estack = ORIGIN(DTCM) + LENGTH(DTCM); /* end of "DTCM" Ram type memory */
_Min_Heap_Size = 0x200; /* required amount of heap */
_Min_Stack_Size = 0x400; /* required amount of stack */
__FLASH_BEGIN = 0x70000000;
__FLASH_SIZE = 0x08000000;
__RAM_BEGIN = 0x24000000;
__RAM_SIZE = 0x6A000;
/* Non-Cacheable Buffer: Increased to 32 KB */
__RAM_NONCACHEABLEBUFFER_SIZE = 0x8000;
/* Memories definition */
MEMORY
{
RAM (xrw) : ORIGIN = __RAM_BEGIN, LENGTH = __RAM_SIZE
RAM_NONCACHEABLEBUFFER (xrw) : ORIGIN = __RAM_BEGIN + __RAM_SIZE, LENGTH = __RAM_NONCACHEABLEBUFFER_SIZE
ITCM (xrw) : ORIGIN = 0x00000000, LENGTH = 0x00010000
DTCM (rw) : ORIGIN = 0x20000000, LENGTH = 0x00010000
SRAMAHB (rw) : ORIGIN = 0x30000000, LENGTH = 0x00008000
BKPSRAM (rw) : ORIGIN = 0x38800000, LENGTH = 0x00001000
FLASH (xrw) : ORIGIN = __FLASH_BEGIN, LENGTH = __FLASH_SIZE
}
/* Sections */
SECTIONS
{
/* The startup code into "FLASH" FLASH type memory */
.isr_vector :
{
. = ALIGN(4);
KEEP(*(.isr_vector)) /* Startup code */
. = ALIGN(4);
} >FLASH
/* The program code and other data into "FLASH" FLASH type memory */
.text :
{
. = ALIGN(4);
*(.text) /* .text sections (code) */
*(.text*) /* .text* sections (code) */
*(.glue_7) /* glue arm to thumb code */
*(.glue_7t) /* glue thumb to arm code */
*(.eh_frame)
KEEP (*(.init))
KEEP (*(.fini))
. = ALIGN(4);
_etext = .; /* define a global symbols at end of code */
} >FLASH
/* Constant data into "FLASH" FLASH type memory */
.rodata :
{
. = ALIGN(4);
*(.rodata) /* .rodata sections (constants, strings, etc.) */
*(.rodata*) /* .rodata* sections (constants, strings, etc.) */
. = ALIGN(4);
} >FLASH
.ARM.extab (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
{
. = ALIGN(4);
*(.ARM.extab* .gnu.linkonce.armextab.*)
. = ALIGN(4);
} >FLASH
.ARM (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
{
. = ALIGN(4);
__exidx_start = .;
*(.ARM.exidx*)
__exidx_end = .;
. = ALIGN(4);
} >FLASH
.preinit_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
{
. = ALIGN(4);
PROVIDE_HIDDEN (__preinit_array_start = .);
KEEP (*(.preinit_array*))
PROVIDE_HIDDEN (__preinit_array_end = .);
. = ALIGN(4);
} >FLASH
.init_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
{
. = ALIGN(4);
PROVIDE_HIDDEN (__init_array_start = .);
KEEP (*(SORT(.init_array.*)))
KEEP (*(.init_array*))
PROVIDE_HIDDEN (__init_array_end = .);
. = ALIGN(4);
} >FLASH
.fini_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
{
. = ALIGN(4);
PROVIDE_HIDDEN (__fini_array_start = .);
KEEP (*(SORT(.fini_array.*)))
KEEP (*(.fini_array*))
PROVIDE_HIDDEN (__fini_array_end = .);
. = ALIGN(4);
} >FLASH
/* Used by the startup to initialize data */
_sidata = LOADADDR(.data);
/* Initialized data sections into "RAM" Ram type memory */
.data :
{
. = ALIGN(4);
_sdata = .; /* create a global symbol at data start */
*(.data) /* .data sections */
*(.data*) /* .data* sections */
*(.RamFunc) /* .RamFunc sections */
*(.RamFunc*) /* .RamFunc* sections */
. = ALIGN(4);
_edata = .; /* define a global symbol at data end */
} >RAM AT> FLASH
/* Uninitialized data section into "RAM" Ram type memory */
. = ALIGN(4);
.bss :
{
/* This is used by the startup in order to initialize the .bss section */
_sbss = .; /* define a global symbol at bss start */
__bss_start__ = _sbss;
*(.bss)
*(.bss*)
*(COMMON)
. = ALIGN(4);
_ebss = .; /* define a global symbol at bss end */
__bss_end__ = _ebss;
} >RAM
RW_NONCACHEABLE :
{
__NONCACHEABLEBUFFER_BEGIN = .;/* create symbol for start of section */
KEEP(*(noncacheable_buffer))
__NONCACHEABLEBUFFER_END = .; /* create symbol for start of section */
} > RAM_NONCACHEABLEBUFFER
/* User_heap_stack section, used to check that there is enough "RAM" Ram type memory left */
._user_heap_stack :
{
. = ALIGN(8);
PROVIDE ( end = . );
PROVIDE ( _end = . );
. = . + _Min_Heap_Size;
. = . + _Min_Stack_Size;
. = ALIGN(8);
} >DTCM
/* Remove information from the compiler libraries */
/DISCARD/ :
{
libc.a ( * )
libm.a ( * )
libgcc.a ( * )
}
.ARM.attributes 0 : { *(.ARM.attributes) }
}
2026-01-08 3:04 AM
Perhaps it has escaped your attention that an ADC has a linear electrical component as well.
Nowhere have you described this relevant electrical parameters like input voltages, input impedances, or conversion times.
And I would recommend to read up on multiplexed SAR ADC, to understand how you need to design and configure it.