Some Question About Inchworm

Anyone reading this should note that this is a handbuilt inchworm board not an inchworm kit. To ensure the processor has everything it needs to run we are programming a pic to blink the busy LED on the inchworm.

Ayne said:

i write the code and feed it to the PIC, now the programmed pic is running fine on my Develpment board, it is blinking LED connected at PORTB.3.
But when i insert the same PIC into Inchworm it not blink LED.
But when i apply direct 5 volts to PORTB.3 in Inchworm IC's Socket then LED turn ON.
As i understand this is because MCLR/VPP pin is not pulled up with any resistor to positive supply in Inchworm.

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For this to work you must have programmed the PIC for use with a HS osc. I assume this is not a problem.

Try hooking a 10K resistor between positive and PIC pin 1. That should pull it high as needed.

Finsh this test. get it to blink then look at the RS232 if there is still a problem.

I have test my RS232 cable and MAX232 at both speeds 57600 and 19200 they r right....... I use "Input Output monitor". It is not a complier, it is just like a Terminal program comes with PICC compiler...

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It is good that it worked buy you still need to check/inspect/(look at) all the wires/connections between the Inchworm PIC the MAX232 and the RS232 connector on the inchworm.

Many people here got blank Inchworm PCBs from contest entries and such, so its not uncommon. Attached is the 16F877A Inchworm firmware with OS preloaded. And make sure LVP is off when using your TAIT or put a 1K resistor between RB3 and GND on the Inchworm (and then program another 16F877A with the Inchworm) use it and remove the resistor. This will disable the Busy LED but your Inchworm should run even if the chip was programmed with LVP enabled.

Now i tell you from start(I have read the Inchworm ICD2
Assembly Instructions).
1. I received the PCB of Inchworm from BlueRoom electronics free.... without components..... only only PCB.
2. I bought all the components from local market(PIC16F877A etc etc)
3. I assembled then and do some soldring..
4. I checked my PCB it is looking ok... then i apply electrical power to it.
5. I test PCB at Test Points, the reading are
5 Volts on TP+5 And
12.8 Volts on TP VPP.

6. For checking Serial Cable(RS232) and MAX232, i use a simple terminal program called "Input Output monitor" comes with PICC compiler. I short
RC7 and RC6 with a jumper on IC socket of PIC16F877A on Inchworm, i send some data from Terminal, terminal receive same data which i was sent a few micro seconds ago. I remove the jumper from socket and send data again and no data received. It means my cable and MAX232 is right and working corectly.


7. I have another programmer (TAIT Serial Programmer) and it is working... I feed a simple program blinking LEDs into PIC16F877A and for checking that Microcontroller is right...... OO yes. LEDs are blinking on my another develpment board.

8. Now i erase my previous program(blinking LED) and feed a new program "ICD2_Bootloader_A.hex" into PIC16F877A. it programmed successfuly.

9. I turn OFF FIFO of both COM1 and COM2.. and restart my computer

10. I push PIC16F877A into Socket and connect it with Serial port cable.

11. Run MPLAB.

12. I selected ICD2 from programmer menu. and run ICD wizard.

13. I press the connect button but it says

Auto-connect not enabled - Not connecting (Try enabling auto-connect on the ICD2 settings pages.)
ICDWarn0034: Please ensure that your system's serial FIFO buffers are disabled.
Connecting to MPLAB ICD 2
ICDWarn0054: MPLAB IDE has lost communications with the MPLAB ICD 2. Would you like to attempt to reconnect?
Connecting to MPLAB ICD 2
ICD0021: Unable to connect with MPLAB ICD 2
MPLAB ICD 2 Ready
Connecting to MPLAB ICD 2
ICD0021: Unable to connect with MPLAB ICD 2
MPLAB ICD 2 Ready
Connecting to MPLAB ICD 2
ICD0021: Unable to connect with MPLAB ICD 2
MPLAB ICD 2 Ready
Connecting to MPLAB ICD 2
ICD0021: Unable to connect with MPLAB ICD 2
MPLAB ICD 2 Ready
Connecting to MPLAB ICD 2
ICD0021: Unable to connect with MPLAB ICD 2
MPLAB ICD 2 Ready

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What is worng i have done???

Auto-connect not enabled - Not connecting (Try enabling auto-connect on the ICD2 settings pages.)
ICDWarn0034: Please ensure that your system's serial FIFO buffers are disabled.
Connecting to MPLAB ICD 2
...Connected
Setting Vdd source to target
ICDWarn0020: Invalid target device id (expected=0x71, read=0x0)
...Reading ICD Product ID
Running ICD Self Test
...Passed
MPLAB ICD 2 Ready
Running ICD Self Test
...Passed

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Thanks to Lord Allah....
Problem solved...
Bad crystal....
Thank u answering.

In my view crystal should be little above from PCB surface.... I mean crystal not touched with PCB surface....

i too was getting #21 error
untill i got my ICD2 oscillator working.
have you got another clock source available?

i used a 100 ohm resistor , neither part was damaged.
and i touched pin 13 of the F877 on the ICD2 board , and clicked connect at the same time , and it worked.

EDIT of course the two grounds have to be connected also

Ayne said:

In my view crystal should be little above from PCB surface.... I mean crystal not touched with PCB surface....

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Quite right, not too snug as most crystals have metal bottoms that may short out against the pads on the PCB. Some series cut crystals may overdrive the PIC, I'll look into ones that work and post a digikey part number in the assembly manual.

1. I received the PCB of Inchworm from BlueRoom electronics free.... without components..... only only PCB.

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I did not know you had the PCB. Was thinking you were hand wiring it. That is why I was so concerned with the RS232=MAX232=PIC wiring.

Hand wiring is how I made the prototype, wasn't as reliable as a pre etched PCB though.

blueroomelectronics said:

Hand wiring is how I made the prototype, wasn't as reliable as a pre etched PCB though.

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Wow.... How big was it? That had to be a terrible knot of wires on the bottom.

Andy1845c said:

Wow.... How big was it? That had to be a terrible knot of wires on the bottom.

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Not too bad actually, only 2 ICs. I use wire-wrap wire but solder it point to point. The USB version looked far worse.