can't read any 12c508/9

[lc]

Hi,

Using JDM and ICprog

I can't read anything out of a 12c508 or 509 (tried several)
however I can program them, as they execute the code
correctly afterwards. Of course I get the VERIFY fail at 0000
as the software can't read the device to perform the verify.

This is only with the 508/9 as for example on the 16F84 all
works without any problem whatsoever.

I even inspected the communication with the device using a logic
analyzer, and the communication method looks the same for both
the 12c508 and 16f84 as should be according to the datasheet.
However the 16f84 gets out of the input mode and responds
with the appropriated data while a 12c508 stays always at high impedance
and I read all words 03ff.

Does anybody knows what is wrong ?
Is there anybody that program and reads 508's with ICprog + JDM ?

Thanks.
Luis Cupido.

 

[Michel Catudal]

Hi,

Using JDM and ICprog

I can't read anything out of a 12c508 or 509 (tried several)
however I can program them, as they execute the code
correctly afterwards. Of course I get the VERIFY fail at 0000
as the software can't read the device to perform the verify.

This is only with the 508/9 as for example on the 16F84 all
works without any problem whatsoever.

I even inspected the communication with the device using a logic
analyzer, and the communication method looks the same for both
the 12c508 and 16f84 as should be according to the datasheet.
However the 16f84 gets out of the input mode and responds
with the appropriated data while a 12c508 stays always at high impedance
and I read all words 03ff.

Does anybody knows what is wrong ?
Is there anybody that program and reads 508's with ICprog + JDM ?

Thanks.
Luis Cupido.

You probably programmed the protection bits. This is normal. If you want
to be able to read it back don't program the copy protection.