Problem with PS Configuration Using USB Blaster Cyclone III - EP3C5E144I7N

[Altera_Forum]

Hello together, 

 I design a custom board with an Altera Cyclone III - EP3C5E144I7N FPGA and a microchip pic microcontroller. In the first step the FPGA will be program from an Altera EPCS4 flash device. This works fine.  Later I want remove the EPCS4 flash device. Then I want to program the FPGA by the pic microcontroller in passive serial configuration mode. Before I do that, I try to program the FPGA in passive serial configruation using an usb blaster. This is why I have to modify the schematic as shown in the attachment. The Mode Pins are selected as described below: MSEL2=0 MSEL1=0 MSEL0=0  If I want to programm the device, I got an error message "Unable to reset device before configuration. Configuration failed.".   Has anybody an idea what's wrong?  Thank You.  Br, Carsten

[Altera_Forum]

Your design does look relatively complicated, which isn't going to help. You've clearly tried to design in a number of options. 

 I can't see anything schematically wrong with it, assuming your 'disconnected' traces are just that. So, I have to assume something in the circuit is causing one or more of the signals to/from the FPGA a problem. Have you an oscilloscope to help you diagnose this? If so, you need to put it to use and look for activity on all the configuration signals and confirm any activity you find has good signal integrity.  If you don't have a scope then you are going to have to start removing bits that aren't required for PS boot and see what's affecting the circuit. U2 and the PIC are good candidates to start with.  Regards, Alex

[Altera_Forum]

Hi Alex, 

 thank you for your help. I have solve the problem. There was a mistake on the pcb. The schematic was ok.  Thank You.  Regards  Carsten