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Alexmouse
Alexmouse
Associate III
December 15, 2022
Question

DAC not responding

  • December 15, 2022
  • 4 replies
  • 2234 views

I'm using the STM32H745I-DISCO board.

I'm trying capture on the ADC and feed straight out on the DAC, triggered by a timer.

The timer is working, and the ADC is getting data that looks sensible.

I can see data reaching the DAC data register, but the output is sitting at rail.

My signals are:

ADC1 IN0 PA0_C T1 Arduino connector CN7 pin3

DAC1 OUT1 PA4 U3 STMOD connector P1 pin13

I'm calling HAL_DAC_Start(&hdac1, DAC_CHANNEL_1);

at startup, then

HAL_DAC_SetValue(&hdac1,DAC1_CHANNEL_1,DAC_ALIGN_12B_R,(uint32_t)Sample_ADC)

I've tried various options in CubeMX without success.

7.2. DAC1 - OUT1 connected to: only external pin

Initialized Context: Cortex-M7

DAC Out1 Settings:

Mode selected Normal Mode

Output Buffer Enable

Trigger None

User Trimming Factory trimming

Did I miss something?

This topic has been closed for replies.

4 replies

RomainR.
RomainR.
ST Employee
December 15, 2022

Hello Alexmouse (Community Member),

Are you able to drive DAC OUT1 with a know static code that you could easily measure ?

Could you try Cube_FW_H7 DAC example: \STM32Cube\Repository\STM32Cube_FW_H7_V1.10.0\Projects\STM32H745I-DISCO\Examples\DAC\DAC_SignalsGeneration1 ?

Best regards,

Romain,

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Alexmouse
AlexmouseAuthor
Associate III
December 15, 2022

I ran that example (CM7 DAC_SignalsGeneration), and have the scope on STMOD connector P1 pin13, DAC1 OUT1 PA4.

The output is still sitting at ~Vcc.

Alexmouse
AlexmouseAuthor
Associate III
December 15, 2022

I tried a simple ramping value, no change.

I'll take a look at that example.

Alexmouse
AlexmouseAuthor
Associate III
December 15, 2022

Socket P1, I assumed the usual zigzag pin order.

However, it is pinned as per the schematic, along the first row then the second row.

Studying the Gerbers, I found the correct pin.

RomainR.
RomainR.
ST Employee
December 15, 2022

Hi Alexmouse 

It's a good news, yes STMOD+ connector pinout are even and odd ordered.

If you see sawtooth signal from example, you should be very close to the goal.

Best regards

Romain,

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