most modern design for an HP41 rom module?

[Monte Dalrymple]

(08-06-2024 02:34 AM)John Ioannidis Wrote:  

(08-04-2024 02:41 PM)MeindertKuipers Wrote:  Working hard to get to the first Development board version of TULIP4041, and then on to a module version, as Thomas referred to. As Thomas mentioned, this is not a low power solution, but the settings will all be saved when removed from the calculator. More info will come soon, preliminary details are here: https://github.com/mjakuipers/TULIP-DevBoard

Thanks, but not useful if you don't publish the software! I'd be making my own PCB anyway.

While we are at it, why use the combination of 4050 and 40109 to do the level-shifting, instead of just a TXB0108 or an SN74LVC8T245? Are the bidirectional signals open-drain, and only need to be pulled down, in which case something like https://www.adafruit.com/product/757 with weaker pullups would do the trick?

/ji

Both the TXB0108 or an SN74LVC8T245 are 5.5V max. The 41 bus is 6V. The 40109 has much better supply current also.