Sunday, August 16, 2009

Couple of 08 boards revisited

Finally had time to finish and test two boards from 08.

The SLA smart charger from here.

And the SPI Bios programmer based on this project.

The SPI bios programmer worked fine, I substituted the original design's CD4049 with a 74HC04, which is the same functionality-wise but with a different pinout. The small adapter board was made because the SMD pads in the main PCB design turned out to be the narrow version (I didn't double-check during design), and I needed the wide one. Soldered the SST25VF080B onto the adapter, inserted it into the DIP8 socket, and modified the original program code for the smaller chip (the only difference between the original project's SST25VF016B is size. The 016B is 2 megabytes, while the 080B is only 1.
Erased the chip, wrote the new bios, read it back, compared. It worked just fine. (Though the mobo had other problems)

Finally found an SMD LM339 to finish the the SLA Charger. I substituted several componens from the original design, with ones I had at home. It seems to work just fine at the moment, but the power transistor requires substantial cooling. I will have to find some sort of case for this sooner or later.