Re: Mini Boot Strap
- --- In firstname.lastname@example.org, William Donnelly <william@...> wrote:
>You are right, it definitely needs more refinement.
> I think you mis-read the program a bit.
> You might have been "confused" a little because it won't work as shown
> I don't know what he's setting EF4 with, but the way the program reads,The intent is to measure pulse width from EF4. Because, EF4 is the only pin brought out to the DB25 connector on the Membership Card. This program is strictly intended for the the Membership card because it is capable of setting a low clock frequency. Hopefully, low enough that an audio frequency signal from the PC's Audio output can produce.
> it is being used as a "There's a data bit available" flag.
> BUT you can't ALSO use EF4 as the data bit itself. (except possibly as
> Lee noted)
It should be a short program that's not a pain to toggle in. The hardware should be a simple cable, series resistor and clamping diodes to connect the audio out to the EF4. The VIP and other Audio inputs from cassettes typically have an op-amp to square the signal, but I'm hoping the PC can produce adequately square signals without the need for extra hardware.
> ; Note that you could also use: (might be some minimal cycle count /Yes, I like it. Load and clear
> speed difference)
> ;04 LDI ; load 02 hex = 00000010 binary byte-wise
> ;05 02
> ;06 SHR ; clear carry and set D = 01 hex
- --- In email@example.com, "jdrose_8_bit" <rarecoinbuyer@...> wrote:
>Magstripe ABA format for Track 1... is "Up to 79 ALPHA 7-bit (including parity) characters (alphanumeric) including SS, ES and LRC."
> What about those plastic ID cards that have the magnetic strip on them. Wonder if they would hold 256 bytes of program code?
I have a number of magstripe card readers if anyone wants one to play with, I'll be happy to send one for just the price of postage.
> I also like the idea of a punched paper reader. That would be a hoot.Agreed!
> (There is a fellow on YouTube who made a complete computer out of relays. Including a printed paper reader to load programs.)Very cool video! Nicely made computer. I definitely have to build one of those some day!