PIC not operating!

[DanielPIC32]

Hello,

I have created a small pcb with (hopefully) all required components to support a PIC32mx360f512l, but it is simply not operating! I am using a junebug and pickit 2.61 set to pic32 device family, I was previously using the junebug for power (regulated by the voltage regulator pictured on the top left of the schematic)
but now am using a adjustable power supply feeding directly to the pic. When powered by the junebug pickit2 opens a dialog box and states: "pickit2 vpp voltage error. check target and retry." and powered by the power supply: "no device detected." however, when not powered pickit 2 says: "PIC device found." !

The schematic is attached in pdf. Please notify me if other formats are required.

By the way, excellent website and forum!!

 

[Vizier87]

Hi Daniel, welcome to the forum.

From my experience with PICs, the voltage regulator has a very low resistance output between 5V and GND when it is powered up.When you use ICSP programming, the error is seen as if 5V and GND is shorted. I measured the resistance of my regulator between 5V and GND when it is powered up, and that happened, it might be the same with yours.

Cheers,
Vizier87

 

[DanielPIC32]

drawing amps, but not programming

Vizier87, your advice worked! I bypassed the voltage regulator and I saw amps being drawn! however, the junebug failed to communicate with the pic. I assume that mclr is not actually doing the sequence and getting the pic into programming mode.

Thanks, Vizier87

 

[DanielPIC32]

Mclr operating!

I just analyzed mclr with my oscilloscope, and the waveform matches the ones illustrated in the pic32 flash datasheet. As mentioned previously, the pic is running, but is not communicating with the junebug.

 

[Vizier87]

however, the junebug failed to communicate with the pic. I assume that mclr is not actually doing the sequence and getting the pic into programming mode.

Hi, I remedied the same problem by isolating the ground between the regulator and the PIC using a state switch. When you want it in programming mode, pull the switch so that the GND of the PIC isolates itself from the GND of the regulator. When you want to operate the PIC from a separate power, reconnect the ground common between the PIC and the regulator. It worked for me.