Skip to main content
Associate II
June 26, 2023
Solved

What is the maximum supported rate for SPI peripherals on stm32h503rbt6u chips in slave mode?

I use spi1 as the slave to receive data, and if the speed of the spi master is set above 11M, the data received will be misaligned.I would like to know what is the maximum speed supported by the SPI peripheral on the stm32h503rbt6u chip in the slave mode?

This topic has been closed for replies.
waclawek.jan
waclawek.janBest answer
Super User
June 26, 2023

How does the physical connection look like? Can you show photos?

What are the logic levels at both sides?

Is NSS low all the time during transmission?

JW

10 replies

gbm
Super User
June 26, 2023

And what exactly do you mean by "misaligned"?

My wild guess is: if by "misaligned" you mean missing/extra frames then it has nothing to do with hardware but rather depends on software - the software reaction time. It's generally hard to implement an intelligent (responding to commands) SPI slave with a microcontroller.

If it's a hardware thing and you see bits being "midaligned" then check the speed setting of all SPI lines on both sides. In particular check if master NSS output (usually software-controlled GPIO) is set to maximum speed.

My STM32 stuff on github - compact USB device stack and more: https://github.com/gbm-ii/gbmUSBdevice
Associate II
June 26, 2023

taylor_quan_0-1687780370594.png

As shown in the above figure, when the speed set by the spi master exceeds 11M, the data sent by the slave appears to have lost bits

AScha.3
Super User
June 26, 2023

from ds :

AScha3_0-1687781775812.png

 

so 120MHz max.   ; how long are the wires ? ground /shield ? damping resistors ?

 

If you feel a post has answered your question, please click on " Best Answer ".
Associate II
June 26, 2023

May I ask which document should I refer to for this image? I am using a DuPont cable, and the master and slave devices use the same ground

 
AScha.3
Super User
June 26, 2023

cpu data...

AScha3_0-1687784255663.pngAScha3_1-1687784285379.png

 

 

If you feel a post has answered your question, please click on " Best Answer ".
waclawek.jan
waclawek.janBest answer
Super User
June 26, 2023

How does the physical connection look like? Can you show photos?

What are the logic levels at both sides?

Is NSS low all the time during transmission?

JW

Associate II
June 26, 2023

taylor_quan_0-1687783615600.jpeg

The physical connection is shown in the figure above.
The logic level is all 3.3v.
NSS has always been low, but it is not used in firmware

taylor_quan_1-1687783646421.png

 

waclawek.jan
Super User
June 26, 2023

Read the article I linked to.

12MHz is not a trivial frequency.

JW