Could you help me with the Kempston interface on the daughterboard?
I can't make out for sure where the pins for the directions and fire are.
http://img5.imageshack_.us/img5/9717/vfghf.jpg
Вид для печати
Could you help me with the Kempston interface on the daughterboard?
I can't make out for sure where the pins for the directions and fire are.
http://img5.imageshack_.us/img5/9717/vfghf.jpg
Part of the circuit which implements the interface joystick. There are two options. Fire - or 8 output chips, or 11.
Not rule out that wiring is faulty (or just very specific divorced).
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Shockwav3, my advice, just load the game and run with selected kempston-joystick option, then try to connect unknown pins IDC10 to GND and see what happen on screen.
Yes, I've already checked the board against the scheme. While the Pins for left (13) and right (11) are obvious, the other pins connect to legs 4, 6 and 8 on the chip :(
it isn't important as inputs are connected, the main thing that was compliance an input output of AP3 and were connected to appropriate bits of the data bus. 1533AP3 (SN74ALS240) is 8-bit data bus tranciever with inverted outputs.
Небельмеса
I have checked wires on the PCB:
I've soldered a D-Sub 9 port as described, but for some reason it does not work.
When using "10 PRINT IN 31;:GO TO 10" in basic for testing I get a constant value of 255. It doesn't matter if I have a joystick connected or not.
Symbols of diodes VD3 - VD5 are misdirected on the picture of this PCB for 1N4148 diodes. Cathodes of all diodes must be connected to pins 1, 19 of DD7:
I think I read that somewhere before, which is why they're connected opposite of the pcb prints on my board. 1n4148Цитата:
Сообщение от Mdesk
EDIT3: We're getting there, adjusting the R11 with the faulty value of 1k-Ohm to 1m-Ohm allows me to access TRDOS and _randomly_ the Joystick (Test program returns values like 00000255255255, etc.)
EDIT4: It's working :) Bypassing the diodes and sending /OIRQ, /RD and A5 through OR-Gates as shown here (http://8bit.yarek.pl/hardware/zx.joystick/kjschem.gif) the kempston Joystick works along with TRDOS access.
Maybe that's something that could be fixed on the next Revision of the board?