HP-71b - Future "SD-RAM" Module - viable ?

[Jeff_Birt]

A friend of mine came up with this serial interfaced SD card 'drive' a while ago. Primarily he made it to emulate the Tandy Portable Disk Drive 2 for the Model 100, etc. We had a batch made up and then the chip shortage

He has since developed firmware to support the Epson HX-20 and PX-8. It also works with the Sinclair Z88 with a few TPDD-2 clients that were written for it back in the day. He just added XModem support so any RS232 device that supports file transfers with XModem would work as well. So 'if' you had the RS2332 interface for your HP-71 and XModem transfer program, but that sort of defeats the purpose.

He did bring power and the SPI lines out to the DB25 but all other signals are RS-232 levels. Is three TTL level lines enough to do HP-IL? Just thought I would bring it up as an idea of what is out there. I find the size of the device makes is convenient and it runs on a single AA battery.


Link is my website, for informational purposes. They are not available at this time anyhow.
TPDD-2 Backpack