PIC18F4850 will not oscillate

[IRQ_Diode]

Bruce,

I read back the configuration from the PIC, and it returned the following:

0000- 0200 1f17 8200 0081 c00f e00f 400f

Towards the bottom of the window, it has a 0xEB87. I can't really tell what this data means, so I am looking at the DS39622L document from microchip. But I really can't see how those two relate. Page 29, of the document shows the configuration bits and the CONFIG1H is located at 300001h.

Mark_s,

I changed the 18F4580.INC file to comment out the _CONFIG statements and recompiled. I also change the options to the meProg to not "Update configuration from file". I reprogrammed the device, but no luck. I read back the configurations bits and they are the same as above.

Any more ideas?

[IRQ_Diode]

So I made sense of the configuration read back results. And as I imagine the CONFIG1H is not being set by the U2 programmer.

CONFIG1H = 02 (HS Oscillator enabled)
CONFIG1L = 00 (default))
CONFIG2H = 1F
CONFIG2L = 17
CONFIG3H = 82
CONFIG3L = 00
CONFIG4H = 00
CONFIG4L = 81
CONFIG5H = C0
CONFIG5L = 0F
CONFIG6H = E0
CONFIG6L = 0F
CONFIG7H = 40
CONFIG7L = 0F


The configuration file seems to be correct. Can anyone make sense of what is going on?. I have two cards behaving exatly the same.

[Bruce]

When you read the .HEX from the PIC with your programmer, just click the C to view the config settings embedded in the .HEX file. Like you did in post #4.

If it reads back with the settings you expect, then I would have to suspect a bad oscillator, caps, or something in the external osc circuit causing a problem.

Double check those SMD caps to make sure they're not resistors...;o)

[prstein]

Is "Options|Update Configuration From File" checked? It shouldn't be.

Best Regards,
Paul

[IRQ_Diode]

I read the configuration back from the PIC and it reads the correct settings for the oscillator

I have open a ticket with Microchip and contacted melabs to see if they have another idea on how to get this solved. I have tried two different oscillators.

Has anyone used a PIC18F4580 that could let me know what oscillator they used (actual part number)?

[Bruce]

Add this to your config settings just below your _CONFIG2H line;
__CONFIG _CONFIG2L, _PWRT_ON_2L & _BOREN_BOHW_2L & _BORV_3_2L

This should give it more time for the oscillator to start up.

[IRQ_Diode]

Bruce,

I did try your suggestion and added the line:

__CONFIG _CONFIG2L, _PWRT_ON_2L & _BOREN_BOHW_2L & _BORV_3_2L

The programmer read the configurations bits correctly, but the PIC still will not oscillate. I also went and checked the caps just to make sure that they were not resistors, and well they were not.

I am considering that it could be the actual part number of the crystal itself. The only thing I have not tried is to place a series resistor to one side of the oscillator. I would have to cut the trace and make sure that I do not short anything to the ground pour around the oscillator.

So before I do that, is there anything else someone can think of? Microchip is taking its time to respond, and I need to send the gerber files to the manufacturer soon.

Thanks,

IRQ