HP-19C Repair Odysee

[jjohnson873]

(06-04-2021 09:01 AM)PANAMATIK Wrote:  I would really like to program a PIK with a FPGA, but the available FPGAs with the necessary amount of cells are rather big, with many pins and they have 3,3V or 1,8V signals. They would not tolerante the 6,4V power of the HP calculators. And even if the inputs are 5V tolerant, all output signals must be converted to 5V level. I cannot see a minimalistic solution which finds place on the small area of a 28-pin package.

Bernhard

Bernhard....have you looked at the Microchip/Microsemi 250MHz, Igloo nano series of flash based FPGAs? They come in as small as a 3x3mm BGA package. Unlikely you'd want to use the BGA package, but you could use the 6x6mm QFN package. You would have to add a voltage translation IC to move from the FPGA 3.3v I/O to 6.4v I/O. The Igloo series is also an ultra low power FPGA.
~ Jim J. ~