The HP 34E Ir with PANAMATIK ACT

[Dave Frederickson]

(09-23-2015 05:44 PM)Harald Wrote:  

(09-23-2015 04:44 PM)Dave Frederickson Wrote:  Very nice, Harald!

Just last week I found on eBay a complete 34C "for parts". I'm considering modifying my 25E Ir, too. As the resident expert on USB cable adapters, what's the part number for the cable you used? With that type of plug I believe it's important to plug it into the calculator before pluging in the USB end, correct?

Dave

The cable is my WP34s flash cable prototype which I hacked from an old USB to RS485 adapter. But any USB to UART cable should do.

The USB needs to be plugged in first, the Calculator after starting Bernhards flash tool. This is necessary because of the way he gets into the bootloader.
You have to take care that Vcc is the last connection to be made on the jack. If this isn't the case you can (and will, as I found out the hard way) damage Bernhards ACT.

I'm concerned that the connections are made simultaneously. At microcontroller speeds it's possible for Vcc to make contact before the Tx pin.

USB is designed to be hot-plugged, consequently the power pins are longer and make contact before the data pins. I've installed a micro-USB receptacle inside the battery compartment and wired the connector so Gnd and Tx are connected to the long pins and are assured of making contact before Vcc.

Micro-USB breakout board positioned with double-sided foam tape.
https://drive.google.com/open?id=0B-GPxm...lpiQTJmWTA

Silicone adhesive added for strength.
https://drive.google.com/open?id=0B-GPxm...jJodjdJQkE

All wired. Essential tools in background.
https://drive.google.com/open?id=0B-GPxm...3JJYzkyWFE

Blind-mate the case halfs.

Cable unplugged.
https://drive.google.com/open?id=0B-GPxm...k1oUzVPTG8

Cable plugged in.
https://drive.google.com/open?id=0B-GPxm...ERMeTdUTVk

Here's the problem. The ACT won't program when plugged into the 25. Unplugged it programs fine.

Dave