Hello, when I googled RPN calculators i found the threads in this forum about the wp 34s. The idea with a updateable scientific calculator with rpn in 42s style is interesting. As I have an hp 20b I thought I should try your firmware.
My problem is the cable. My questions is if I can use an UB232R module with ftdi chip http://www.ftdichip.com/Products/Modules/DevelopmentModules.htm and datasheet
As I understand it i need to sett the reset and erase
line high manually some times in the flash process so I need two a (debounced?) button to do this. I found some threads with information about use a ftdi ship to get serial communication. Do this solutions works to flash the unit also, or is it necessary with some solution to set reset and erase high to use this solutions to the flashing procedure?