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Homemade Z80 Computer Project

Discussion in 'Microcontrollers, Programming and IoT' started by Electronics_Wiz, Jan 16, 2018.

  1. Electronics_Wiz

    Electronics_Wiz

    4
    0
    Jan 16, 2018
    Hello everyone! This is my first time posting on this forum. I signed up because I am having a bit of trouble with my Z80 computer ( depicted below the code ). I already put the computer on a perforated board, but the system does not seem to output any correct data. Here is the code that I programmed into EEPROM:
    Code:
        org 0x0000
    uart_init:
        ld a, 0x80
        out (0x03), a
        ld a, 12
        out(0x00), a
        ld a, 00
        out(0x01), a
        ld a, 0x03
        out(0x03),a
    uart_out:
        in a, (0x05)
        bit 5, a
        jp z, uart_out
        ld a, 0x41
        out (0x00), a
        jp uart_out
    z80_system_IO.png z80_system_memory.png z80_system_processor.png
     
  2. Electronics_Wiz

    Electronics_Wiz

    4
    0
    Jan 16, 2018
    NOTE: There is a problem I found, that is that two of the CS pins on the UART are tied low when they should be high. This is a simple error in the schematic, but is not present in the system I already have built. Also, the processor seems to be able to activate the UART, as the UART does print data. The only thing is that the data is just a bunch of random characters.
     
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