LB-Z80-01

Features

• Z80 CPU
• Oscillator 8 MHz nominal on card
• Reset switch/power monitor
• Address decoder PLD drives RAM/ROM/IO chip selects
• 100x50mm card

Memory Map

• 0x0000-0x1FFF 8KB ROM
• 0x2000-0xFFFF 56KB SRAM
  • LB-MEM-02 has 32 KB ARAM w/ 24KB
  • LB-MEM-03 has 128KB or 512 KB of SRAM so 56 KB can be available
• I/O
  • 0x00-0x7F - Free
  • 0x80-0x81 - Serial port (ACIA)

Design

CPU and Power Supervisor/Reset

• Z80 CPU
• Oscillator 8 MHz nominal on card
• Reset switch/power monitor

Memory Access Timing

I/O Access Timing

Oscillator

• 8MHZ or 10 MHz oscillator

PLD

• ATF16V8B part
• TL866ii Plus Programmer

PLD Listing

Name       LB-Z80-01_PLD;
Partno     ATF16V8B;
Date       09/17/20;
Revision   01;
Designer   DOUG G;
Company    LAND BOARDS LLC;
Assembly   LB-Z80-01_U2;
Location   Rustbelt, US;
Device     G16V8;

/*
*/


/* Control inputs */
PIN    1   = CLK;
PIN    2   = CPUA13;
PIN    3   = CPUA14;
PIN    4   = CPUA15;
PIN    5   = !MREQ;
PIN    6   = !IORQ;
PIN    7   = !M1;
PIN    8   = !CPURD;
PIN    9   = !CPUWR;

/* Address Decode and Chip Select outputs */
PIN    13  = !ROMCS;
PIN    14  = !IOCS;
PIN    16  = !MEMRD;
PIN    15  = !RAMCS;
PIN    18  = !WAIT;

ROMCS = !CPUA15 & !CPUA14 & !CPUA13 & MREQ & CPURD;

RAMCS = CPUA15 & MREQ
#       CPUA14 & MREQ
#       CPUA13 & MREQ;

IOCS = !M1 & IORQ;

WAIT = !MREQ # !IORQ;

MEMRD = CPURD;

Backplane Connector

Software

• SIMPLE-Z80 Software

Mechanicals

Checkout

Rev 1

• Didn't use silkscreen values, used
  • R1 = 4.7K
  • Other resistors are 10K
• Z80 nop tester nop = 0x00
  • Refresh complicates this

Assembly Sheet

• Interactive BOM