RE: TI-H: PIC's and TI-89's
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RE: TI-H: PIC's and TI-89's
ok.. I can explain how u can do it...
When you send from the TI to the PIC you can do like this.
You have 2 pins to use on the calculator, in one of them you can send
clock-pulses (PIN_1), and the other one the bits you want to transfer
(PIN_2).
How it works on the calculator :
1. If the Bit to transfer is high, do the PIN_2 high, else do it low.
2. Do the clock-pin (PIN_1) low.
3. Have a delay.
4. Do the clock-pin (PIN_1) high (finnish the clock-pulse).
5. Have a delay.
6. GO around, jump to 1 until you are finnished with the byte.. 8 times
i think..
How it works on the PIC :
1. Waiting for the clock-pin (PIN_1) on the calculator to go low.
2. When it does.. check the pin with the Bit to send (PIN_2).
3. Waiting for the clock.pin (PIN_1) on the calculator to go high.
4. GO around 8 times until you have the byte to transfer.
I think you must have positive pull-up resistors on the PIC's
input-pins. Because you can only have the calculator-port Low.. never
High (atleast on my TI-85). And remember to change the PIC's port to
input-mode.
/PEK