Unable to program 16F877 mcu using ICSP. Please advise....

[arunb]

Hi,

I am able to program 16F628 16F648A mcus, but I am unable to program 16F877 mcu using ICSP.

I have checked the pins for the correct logic and these are ok.

Please advise what is wrong .....


thanks
arunb

[Mark]

With all the information that you have given us, it is your setup.

[arunb]

Hi,

Sorry about the sketchy data I provided....

Well here are the details

Power up is done in the following sequence

1. PGM,PGC,PGD = 0 V
2. MCLR = 13.87 V
3. VDD=5 V (Both the pairs)
4. VSS=0 V (Both the pairs)

Note: Sometimes the PGM goes to 0.7 V ... Why ???

A program word is loaded as per the sequence

1. Load Data for Program Memory - 0010
2. The Program Word is clocked out LSB first
3. Begin Program cycle Command- 011000
4. Increment Address- 0110

The configuration Word is read as follows

1. Load Configuration- 000000
2. Configuration Word is Clocked out LSB first
3. Increment Address Command is sent 7 Times ( 0110)
4. Begin Erase/Program cycle is clocked out.

The Program memory is read as follows

1. Read Data from Program memory 0100
2. Data is clocked in LSB first.
3. Increment address- 0110

A Bulk erase is done as follows.

1. Load Configuration command - 000000
2. Increment address 7 times - 0110
3. Bulk Erase Setup 1- 000001
4. Bulk Erase Setup 2- 000111
5. Begin Erase/program cycle- 001000
6. Bulk Erase Setup 1 - 000001
7. Bulk Erase Setup 2 - 000111

8. The programmer is reset. (Power down , delay then power up)
9. Load data for program memory- 0010
10. Load 0x3FFF
11. Bulk Erase Setup 1- 000001
12. Bulk Erase Setup 2 -000111
13.Begin Erase/program cycle-001000
14. Bulk Erase Setup 1- 000001
15. Bulk Erase Setup 2- 000111
16. The programmer is reset


The voltage levels remain the same througout these operations, the programmer may be reset by bringing voltage levels to 0 and then raised as per the sequence given above.

The programmer works well with a 16F628,16F648A but not with 16F877.


thanks
arunb

[Mark]

What programmer are you using?

[arunb]

Hi,

I made my own programmer , I am trying to use the ICSP technique for programming the 16F877...


thanks
arunb

[Mark]

I'll let someone else take care of this. I don't have time to trouble shoot a home brew programmer but I am about 99.999% sure that it is the programmer.

[arunb]

Hi,

Quite right...

thanks
arunb