LB-6802-01

Features

• 68B02 CPU
  • 1.8432 MHz clock
  • MC6802 is fully compatible with MC6800 but without messy two-phase clocking

Memory Map

• 0x0000-0x7FFF 32KB SRAM
• 0x8000-0xBFFF Serial (68B50 ACIA)
• 0xC000-0xFFFF 16KB EPROM

Design

CPU

MC6800 Block Diagram

Bus Timing

Power Supervisor/Reset

PLD

• ATF16V8B part
• TL866ii Plus Programmer

PLD Listing

Name       LB-6802-01_PLD;
Partno     ATF16V8B;
Date       08/24/24;
Revision   01;
Designer   DOUG G;
Company    LAND BOARDS LLC;
Assembly   LB680201_U2;
Location   Rustbelt, US;
Device     G16V8;

/*
*/


/* Control inputs */
PIN    1   = CLK;
PIN    2   = CPUA12;
PIN    3   = CPUA13;
PIN    4   = CPUA14;
PIN    5   = CPUA15;
PIN    6   = CPUREAD;
PIN    7   = VPB;		/* Added as wire on Rev 1 PCB	*/
PIN    8   = VPA;
PIN    9   = VDA;

/* Address Decode and Chip Select outputs */
PIN    12  = !ROMCS;
PIN    13  = !IOCS;
PIN    14  = !MEMRD;
PIN    16  = !RAMCS;
PIN    18  = RDY;

ROMCS = CPUA15 & CPUA14 & VPB;

RAMCS = !CPUA15 & VPB						/* 0x0000-0x7FFF 32KB SRAM */
#        CPUA15 & !CPUA14 & !CPUA13 & VPB;	/* 0x8000-0x9FFF Free (8KB	*/

IOCS = CPUA15 & !CPUA14 & CPUA13 & VPB;		/* 0xA000-0xBFFF Serial (ACIA)	*/

RDY = VPB;

MEMRD = CPUREAD & VPB;

Backplane Connector

Software

• Simple-6802 Software
• How to Program and Interface the 6800 By Andrew C. Staugaard, Jr. 1980
• 6800 instruction set

Mechanicals

Checkout

Rev 1

• Power supply noise trips voltage monitor
  • Change C2 capacitor to 100 uF

Assembly Sheet

• Interactive BOM