dsPIC not responding

[dsPICgy]

Hi,

I built a dsPIC board using dsPIC33FJ128MC802 (a 28-pin DIL package IC). I have been trying to get it to work but no luck so far. As a DC source, I use a USB connector B which is connected to my PC. This gives +5V to the board which I feed to LM317 voltage regulator. The output of this regulator is fed to VDD of my dsPIC. I have connected 100nF decoupling capacitors between AVDD (pin 27) and AGND (pin 28), and also between VDD (pin 13) and GND (pin . AVDD and AGND are connected to VDD and GND respectively. For MCLR pin, I have a pull-up of 10kOhm and a 1kOhm in series to MCLR pin. I also have a 100nF decoupling to MCLR pin. Lastly, I have a 220nF ceramic capacitor connected across VDDC (pin 20) and GND (pin 19). I know that the datasheet requires a capacitor with capacitance of min 1uF and max 10uF. However, I have seen in a recent post that .1uF capacitor is also okay (see the post "dsPIC refuses to run!" by  szhang on 3 Oct 08). I have not connected any crystal on OSC1 and OSC2 pins. I assume that dsPIC would use its internal FRC oscillator.

As a programmer I use MPLAB ICD 2 and I make a connection to ICD 2 using a 6-pin RJ11 socket where I connected: MCLR to pin 1 of RJ11, VDD to pin 2 of RJ11, GND to pin 3 of RJ11, TX/PGD to pin 4 of RJ11 and RX/PGC to pin 5 of RJ11.

I put all of my components on a stripboard. I have the following voltage measurement on the pins:

MCLR (pin 1): 3.48V
VDD (pin 13): 3.52V
VDDC (pin 20): 2.60V
AVDD (pin 28): 3.52V
The rest of the pins have 0.0V

These measurements were obtained using my multimetre. To this end, everything seems fine. I then connected MPLAB ICD 2 and I obtain the following message:

Connecting to MPLAB ICD 2
...Connected
Setting Vdd source to MPLAB ICD 2
ICDWarn0020: Invalid target device id (expected=0x629, read=0x0)
...Reading ICD Product ID
Running ICD Self Test
...Passed
MPLAB ICD 2 Ready

It seems that my dsPIC is not responding at all. Any suggestion, help or comment is greatly appreciated.

Note that I have also tried using crystal oscillator. I do not have a 8MHz crystal, but I have a 14.7456MHz crystal. Connected this crystal with the associated capacitors to OSC1 and OSC2 pins, I ran into the same problem. Tried with another dsPIC33FJ128MC802 IC, I had the same message from MPLAB. I really run out of idea. Please guide me.... Many thanks in advance.

[ArcMan]

I assume that dsPIC would use its internal FRC oscillator.

I use PIC 16F's, not dsPICs, so take my post with a grain of salt.

You can't assume anything.  You have to set your FUSEs to define the oscillator, low-voltage programming (LVP), etc.  Make sure you shut off LVP unless you are going to use it.

[dsPICgy]

Many thanks for your input, however I did try with a 14.7456MHz crystal (with the associated capacitance) and I ran into the same problem.

[szhang]

From what I see, ICD can't identify your device.  You should be able to program it even without an oscillator, so that probably isn't your problem.

Also, I lied, you can't use a .1uF cap.  For me the programmer and most peripherals worked, but interrupts go wonky if that capacitor is off.  Be sure to use a tantalum capacitor for that (I think ceramic disks works too).

[ellize]

Hi there!

May I ask if you could give me a copy of the MPLAB ICD 2 installer?

[jka]

I know that the datasheet requires a capacitor with capacitance of min 1uF and max 10uF. However, I have seen in a recent post that .1uF capacitor is also okay (see the post "dsPIC refuses to run!" by  szhang on 3 Oct 08).

Try to use a 1-10uF tantalum capacitor as the datasheet says. Even though out-of-spec capacitors work for other users, it might not work in all cases.