Re: HW and electrical transformer/coupler, now: MLDL2000 Message #10 Posted by Meindert Kuipers on 15 Apr 2003, 2:56 a.m., in response to message #6 by Vieira, Luiz C. (Brazil)
I am still worlking hard on my MLDL2000, and there is some progress. I could not spend as much time as I wanted lately but I am now back on the track again. There will be an interface to the outside world, based on a very simple 3 or 4 wire synchronous protocol. This would support a parallel interface to a PC by bit banging the PC's parallel port. I am already investigating USB controllers which are almost single chip solutions between USB and a number of parallle bits, and that would give the MLDL2000 a nice USB interface. Please note that software has to be written as well, both on the PC and HP41 side.
The interface is primarily intended to be able to load and save the ROM and RAM in the MLDL2000.
As for the status of the MLDL2000: I am currently implementing the WROM instruction, but there is a nastly little bug in the state machine that I am trying to resolve. When that is done it is time to do the PC interface.
There are some questions that I would like to ask the forum:
- Is anyome familiar with the HP41 DATA line and how is works when a module supplies data?
- Is there more specific information available on the extra HEPAX instructions? I know what they do but wants some more specifics. It will be very difficult to implement though...
- Bank switching: Is there a complete overview of all the particulars?
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