9810 question and offer

[Tony Duell]

(02-14-2014 07:27 PM)dramsey Wrote:  Here's my question: although the calculator does not have the "Printer Alpha" ROM, program listings include alpha key representations, something like this:

0030 -- |DIV| -- 053

..line number, key, and key code (the above line is made up and I'm pretty sure that's not the key code for the division key). Inserting the Printer Alpha ROM doesn't change a thing.

I thought the Printer Alpha ROM was required for listings like this. Am I wrong?

You do need a Printer Alpha ROM to get the function names in listings, but it may not be a seperate module. Each plug-in module has space for 4 ROM chips, each chips is 512 bytes, they are arranged as 2 sets of 512*16 bits, with a separate chip select line on the connector for each set.

The Printer alpha module only contains 2 ROMs, it's only 512 words long. It can therefore be combined with another 'half size' (512 word) module, I think HP sold combinations of the Plotter+Printer Alpha and the tape cassette+Printer Alpha ROM.

On another point, the card sensors are optical, there are 4 sets of light bulbs and photodetectors arround the card path. It is not clear to me what blocking out one will do, it may well cause other problems in that the unit may be expecting a change of state at each sensor as the card goes through.