HP-41CL Remote Keyboard / Scripting

[PeterP]

(04-17-2021 07:50 PM)rocket.scientist Wrote:  Both SF 11 and mag card would be an excellent option for fully autonomous operation of the 41C. Instead what I am thinking is a way to have the operation of a 41C coordinated with some other asynchronous process.

The updating of a 41CL is a good example, and fairly well known. There is an elaborated dance that needs to happen between a PC and a 41CL to manage the periodic updates, with commands at the PC coordinated with commands on the 41CL. While Sylvain and Monte (and others I am sure) have developed the excellent "clupdate" tool to facilitate, there is still a lot of manual coordination between PC and calc. It would be nice, since the full process is so well known, to have the PC more fully automate the process.

**BIG GOTCHA HERE** This highly automated approach does not accomodate any error conditions that may arise. I am not sure it is possible to permanently brick a 41CL, but I do not want to find out.

-Pat (KG5YPQ)

I have been thinking along the above lines and how to use HP-IL and the amazing PIL-BOX and I think in theory there is a pathway to this.

One could write a program (I am not 100% sure if it can be in FOCAL or would need to be in MCODE) where the HP-IL is sending over Op-Codes. Each Op-Code would relate to a specific function or program in memory which then would be performed, before control is passed back to the HP-IL listening for OpCodes. One Op-Code could be special in that it signifies the start of sending over bytes to be executed. These bytes could then be placed into Alpha where they could be executed with a Sto b into Alpha. This limits the amount of program bytes which can be done to around 23 given that we need a RTN to come out of the Alpha register into main memory again.

But with the ability to perform a)single commands from a) (quasi) unlimited list, b) pre-programmed sequences of steps, and c) ability to perform arbitrary 23 byte program sequences I think one could do a lot of remote scripting from the PC via PIL-Box and HP-IL.