different behaviour when debugging

Question

I'm trying to communicate with an EEPROM chip using SPI. When I run under the debugger, the EEPROM doesn't respond; without the debugger running, it seems to work fine. 
 What difference could running under the debugger be making?

Display Name · Accepted Answer

So, we got it working and the problem was this: 
 The EEPROM has a HOLD pin which needed to be pulled-up in order for it to work. Although the datasheet showed an example schematic with that pin floating (internal pullup implied) that was not the case and an external pullup was needed. 
 We think the debugger/non-debugger difference in behaviour was caused by different levels of noise on the floating pin with/without the debugger running. Bit weird, but 100% reproducible.

different behaviour when debugging

Top Replies