The project i am currently working on is a digital clock using the user's port of that trainer which is configured with the 8255 ic.
I was able to make the hardware work and configure the hardware to use Port A0 to A3 and Port C0 to C5 of 8255 as bidirectional ports to run my circuit.. i'll post the circuit later after i edit it with eagle software.
Just to give you an idea of how circuit uses the ic, I'm currently doing a digital clock hardware project for microprocessors which is purposed to be interfaced with an ANALAB z8 Emulator User's port which is equivalent to an 8255 ic. The power supplied to the emulator is seperated with the +5 V supplied to my circuit.
My circuit uses six common anode 7 segment display to show time with an active low bcd-to-7segment decoder that are limited with 470K ohms resistors. The bcd inputs A,B,C and D are connected to the ports A0, A1, A2, and A3 respectively of the 8255. The six 7 segment displays have been alloted one BC547B NPN transistor each with their collectors connected to +VCC and their bases connected to 330 ohm resistors. The Bases of the transistors are then connected to Port C0,C1,C2,C3,C4,C5 of the 8255. Assuming nothing more is to be done, my problem now is initializing 8255 in my main program to use handshaking of signals.
I have included my program for the chip so you may check on it. Please tell me what i'm doing wrong...
I was able to make the hardware work and configure the hardware to use Port A0 to A3 and Port C0 to C5 of 8255 as bidirectional ports to run my circuit.. i'll post the circuit later after i edit it with eagle software.
Just to give you an idea of how circuit uses the ic, I'm currently doing a digital clock hardware project for microprocessors which is purposed to be interfaced with an ANALAB z8 Emulator User's port which is equivalent to an 8255 ic. The power supplied to the emulator is seperated with the +5 V supplied to my circuit.
My circuit uses six common anode 7 segment display to show time with an active low bcd-to-7segment decoder that are limited with 470K ohms resistors. The bcd inputs A,B,C and D are connected to the ports A0, A1, A2, and A3 respectively of the 8255. The six 7 segment displays have been alloted one BC547B NPN transistor each with their collectors connected to +VCC and their bases connected to 330 ohm resistors. The Bases of the transistors are then connected to Port C0,C1,C2,C3,C4,C5 of the 8255. Assuming nothing more is to be done, my problem now is initializing 8255 in my main program to use handshaking of signals.
I have included my program for the chip so you may check on it. Please tell me what i'm doing wrong...