NP-41 Emulator (may be)

[Chris Chung]

(09-28-2015 11:59 PM)jjohnson873 Wrote:  Hi Chris...very nice display and HP41C emulator in hardware & firmware. I'd be interested in at least one or 10! (is that binary or decimal?). Not sure if I missed it in the thread, but....is there any chance that you're making the electrical connections on the new HP41C display backward compatible with the old HP41C display? There are many, many, many HP41C's (41V's & 41X's) that have damaged displays and would simply need a new one to be fully functional.

Btw....the NP25 went over very well at HHC2015 and there are many new users.
Cheers! Jim J.

I just received the sample LCDs from Waon two hours ago. Will test drive them tomorrow, digit by digit as my PCBs are not ready yet. The current design have the MCU MSP430FR6989 drive the segments directly.

I don't know how the original HP-41C drives the LCDs. From the photos it appears that the LCD is made into a module. We can do the same by using a dedicated driver IC, like the NXP PCF8545 and the likes. They are driver by SPI or I2C so there may be another MCU needs to do the interfacing. I am not sure if there will be a lot of demand on these though.

Glad to hear people playing w/ the NP25C. I was building one this weekend and thought it would be better to move to smd, both the same PCB estate and to eliminate the need for the shift register. For smd packaging, there is an extra 8 pins on the MSP430G2553. Not sure if this will happen though, as my interest is now on the 41.

For the LCD availability, see my previous note on the plans. But 1st I need to make sure the samples are good to drive.