Dataman Forum

I have successfully programmed and erased lots of Atmel 89C55 chip using my S4 with 8751 + 40-44plcc adaptors. Now when I'm using a similar chip with h/w watchog timer, 89C55WD, I can program but not erase the chip, at least not after the security bits have been burnt. This worked with the 89C55. The data book state that both the silicon signature and the programming voltage is different between the two chip. I can't read the silicon signature of the 89C55WD with my S4 and I'm not sure if it was possible with 89C55, I have none left. Does the S4 software try to read the silicon signature to select programming voltage? I have tried the MCS-51 library V1.38 and V1.45. Any suggestions?

Johan

Hi Johan,

Unfortunately there is NO way S4 can program Atmel 89C55WD. This is due to a new algorithm requiring 6.5V on Vcc pin of the chip. Applying this to S4 MCS51 can potentially damage or destroy the module. You can't teach old dog new tricks, I am afraid. So it's a hardware limitation of MCS51 module.

Neil

I also have this problem. The really bad thing is that Atmel are obsoleting the original 89C55 part.
Them people! They crazy!

Ian