Who designed the STM32476G-Disco? Can I pull the LCD off to reveal some test points?

[Donald Bosley]

Posted on April 09, 2017 at 03:46

On Who Designed the board?

RANT: Obviously someone who never had to actually test hardware. When you have two BGA's connected, and no terminating resistors or exposed points in between, test points are a must. Right now, some of the example projects I have downloaded do not run or operate as expected - like the USB Audio demo... so I don't know if I have a code, or a hardware/setup issue. Having no way to test signals, like seeing if I actually have a master clock going to my codec, makes this tool pretty much worthless right now. 

How hard is the LCD fastened and can I pull it off? Will it actually give me any sort of access to any underside vias I could touch with a probe? 

[Tesla DeLorean]

Posted on April 09, 2017 at 18:13

There are Gerbers, so you should be able to check what might be accessible under the LCD

http://www.st.com/resource/en/board_manufacturing_specification/stm32l476g-disco_gerber.zip

 

As I recall the LCD GLASS is socketed, and can be removed by easing it out a bit at a time from alternating ends.

Not sure I see BGA but rather DFU parts

http://www.st.com/en/evaluation-tools/32l476gdiscovery.html

 

[Donald Bosley]

Posted on July 26, 2017 at 03:45

Well typo on my part, it's the 746, which would explain your answer and thank you. Unfortunately, what I found is there are no test points on the 746 board for key lines to and from the CODEC which is a BGA, connected to the MCU, which is a BGA. I scrapped it and spun my own.

[Tesla DeLorean]

Posted on July 26, 2017 at 05:26

Unfortunately as the DISCO boards have evolved they have moved from being convenient break-out type boards to feature rich and pin constrained devices with limited accessibility.  And use parts which are a bugger to work on. The NUCLEO boards went for feature limited, and screwed up USART connectivity. The Arduino shield socket being the saving feature.

These other boards sometimes have an interesting mix of baseline function, and pin escape

https://vcc-gnd.world.taobao.com/

 

[john doe]

Posted on July 26, 2017 at 05:55

weird. the 769disco is loaded with test points around the codec.