AnsweredAssumed Answered

MPC57xx Motherboard 5V SR Problem

Question asked by Luke Zhang on Nov 22, 2018
Latest reply on Nov 27, 2018 by Luke Zhang

Hi all,

 

I'm using MPC5777C 512DS with MPC57XX motherboard (SCH-27237 REV C) for my project. I found a very strange problem and don't know why it happen. The project involves an EEPROM external chip, MCAN module, RS232 module etc. My external EEPROM chip needs 3 pins to connect to 5V, so I decided to use 5V SR line supplying it. There're total 4 5V SR outputs on the top-right corner of the motherboard. Then I found:

 

   1. If I connect 3 of the 5V SR output to that 3 pins on the external chip straightly, my external chip works fine but the MCAN module doesn't work, sometimes RS232 module doesn't work as well.

   2. If I connect 1 of the 5V SR output to a breadboard power line, and from the breadboard power line, I connect 3 output to the external chip, my external chip and all other module work fine.

 

Since all 5V SR has the same effect (they pass the continuity checking), I'm wondering why the first case will cause other module not working. 

 

Regards,

Luke

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