Hi!, On Mon, Feb 2, 2015 at 5:59 PM, Jason White wrote: > I have been able to replicate your setup on the breadboard more or > less, but only if I use separate jumpers. If I use two adjacent > jumpers on a ribbon cable whose insulation is bonded together, it > causes my chip to not be recognized every time for me. I have > replicated this with my STm32F4Discovery Board and my ST-Link on my > prototype. I also have replicated this (again) with my > STm32F4Discovery tried to program itself through bonded jumper wires. > > I am reasonably convinced the jumpers caused the interference in each cas= e. I managed to break the communication by using a 20cm twisted pair cable added to my setup (in the SWDIO and SWCLK lines). The problem is the high frequency spikes in the data and clock signals, an I could solve it by adding 1k terminating resistors (to VCC) on each line, see at: https://drive.google.com/uc?export=3Ddownload&id=3D0B1Uh9dgDfzYpckdIZmtRQ= Ww0Ums I think that the proper value of terminator resistors should be still lower, but less than 2k2 made the setup work. Daniel. --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .