LB-65CXX-01

Features

• 65C02 or 65C816 CPU
• 2 MHz (typical) Oscillator on card
• Reset switch/power monitor
• Address decoder PLD drives RAM/ROM/IO chip selects
• 100x50mm card

Design

Memory Map

0x0000-0x7FFF - 32KB SRAM
0x8000-0x8FFF - 4KB I/O space
0x9000-0xBFFF - Free space (12 KB SRAM Using 128KB SRAM)
0xC000-0xFFFF - 16KB EPROM space

CPU

• 65C02 or 65C816 CPU
  • 65C816 requires mods to the PCB (see Checkout notes below) or Rev 2 PCB
• 2 MHz
• Install jumper J2:1-2 if CPU is not a WDC 65C02 or WDC 65C816

R65C02 vs W65C02 vs W65C816 CPUs

U1 Pin	U1 Pin Name	Sig Name	Pullup	R65C02 sig	W65C02 sig	W65C816 sig
1	VSS/VPB	J2 selects	N	VSS (IN)	VPB (OUT)	VPB (OUT)
3	PH1OUT/ABORT	ABORT*	REV2	PH1OUT (OUT)	PH1OUT (OUT)	ABORT (IN)
5	NC/MLB	MLB	N	NC	MLB (OUT)	MLB (OUT)
7	SYNC/VPA	VPA	N	SYNC (OUT)	SYNC (OUT)	VPA (OUT)
35	NC/E	CPUE	N	NC	NC	EM/NAT (OUT)
36	NC/BE	IORQ*	REV2	NC	BE (IN)	BE (IN)
37	PH0IN/PH2IN	CPUCLK	N	PH0IN	PH2IN	PH2IN
38	SO/MX	CPUMX	REV1/2	SO* (IN)	SOB (IN)	MX (OUT)
39	PH2OUT/VDA	VDA	N	PH2OUT (OUT)	PH2OUT (OUT)	VDA (OUT)

VDA/VPA (65C816)

• VDA/VDA
  • 00, Internal operation (invalid address bus)
  • 01, Valid Program Address
  • 10, Valid Data Address
  • 11, Opcode-fetch

Chip Set

• Ordered from Ebay

• Picture shows 3 MHz CPU
• Received 2 MHz CPU
• As received:

Oscillator

PLD

• ATF16V8B part
• TL866ii Plus Programmer

PLD Listing

• PLD File

Name       LB-65CXX-01_PLD;
Partno     ATF16V8B;
Date       09/12/24;
Revision   01;
Designer   DOUG G;
Company    LAND BOARDS LLC;
Assembly   LB65CXX01_U2;
Location   Rustbelt, US;
Device     G16V8;

/*
	65C02 Control
*/

/* Control inputs */
PIN    1   = CLK;
PIN    2   = CPUA12;
PIN    3   = CPUA13;
PIN    4   = CPUA14;
PIN    5   = CPUA15;
PIN    6   = CPUREAD;
PIN    8   = VPA;
PIN    9   = VDA;		/* Pin 39, PH2OUT - Enable line */

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

RAMCS = !CPUA15 & CPUREAD		/* 0x0000-0x7FFF */
#       !CPUA15 & !CPUREAD & VDA;

IOCS = CPUA15 & !CPUA14 & CPUA13 & !CPUA12 & CPUREAD	/* 0x8000-0x8FFF */
#      CPUA15 & !CPUA14 & CPUA13 & !CPUA12 & !CPUREAD & VDA;

ROMCS = CPUA15 & CPUA14 & CPUREAD;	/* 0xC000-0xFFFF (16KB space)		*/

RDY = VDA;

MEMRD = CPUREAD;

Reset Controller

• DS1813-5 Reset Controller
• 5V Power Monitor
• Reset controller
• Reset pushbutton to ground

Backplane connector

Software

• SIMPLE-6502 Software - Reference software

Assembly Language Development Toolchain

• cc65 Assembler, Linker, Compiler
  • Backup copy
• Example batch file to assemble code and produce .hex file

ca65 AciaTest.s -o AciaTest.o -l
ld65 -C AciaTest.cfg AciaTest.o -o AciaTest.bin
srec_cat.exe AciaTest.bin -binary -o AciaTest.hex -Intel

• AciaTest.cfg

MEMORY {
	ROM:		start = $C000, size = $3FFA, fill = yes, fillval=$FF, file = %O;
	VECTS:		start = $FFFA, size = $6, fill = yes, fillval=$FF, file = %O;
}

SEGMENTS {
	CODE:		load = ROM,	type = ro;
	VECTS:		load = VECTS,	type = ro;
}

ACIA Test Code

• ACIATest.s
• Loopback serial data
• Works

OSI BASIC

• LB-6502 GitHub
• Grant Searle's 6502 design
  • Link to Grant's files
  • Local copy
• Source code
  • osi_bas.s <== the Microsoft OSI BASIC and I/O routines SOURCE all in a single file
  • Grant's I/O routines are at the end of it
• Files to allow the source to be assembled on a Windows based machine
  • assemble.bat <== double click to assemble osi_bas.s and link to binary file "osi_bas.bin"
  • This should be exactly 16K
  • osi_bas.cfg <== configuration file for the linker (ensure ORG and entries in this file match if you change any)
  • ca65.exe <== the assembler from the cc65 package. Use this. The new version on the cc65 site crashes!
  • ld65.exe <== linker from the cc65 package
  • srec_cat.exe <== Converts bin file to .hex file
• Output files
  • osi_bas.bin <== the ROM fine in pure binary
  • osi_bas.lst <== Assembly listing file
  • rom.hex <== the ROM fine in standard INTEL-HEX format
• To allow simple re-assembly, extract all files to the same folder
  • Freeware utilities are available to convert the "bin" file to HEX or s19 (etc) - use your internet search tool to find
• All source code, assembler binaries and the HEX dump of the ROM is here
  • It is in standard INTEL-HEX format for uploading to a suitable programmer.

Simple Monitor 6402

• SimpleMon6502.s - GitHub repo
• Contains
  • ACIA init, read, write
  • Simplest commands mostly for function development
  • String functions - read a string, write a string (macro)

Programming References

6502 Instruction Set

• The 6502 Instruction Set
• 6502 Programmer’s Reference
• 65(c)02 Instruction Set Reference
• 6502 / 6510 Instruction Set

Additional Tools

• 6502 Emulator - Simple emulator but it works
• virtual 6502 / Emulator
• 6502.org Tools for the 6502
  • Cross development package for 65(C)02 systems, including a powerful macro assembler, a C compiler, linker, librarian and several other tools

Mechanicals

Checkout

Rev 3

PCB Updates

• Add bulk electrolytic cap
• Make PH2OUT on VPB backplane line
• Change to vertical reset switch
• Add an LED that is written by writing D0 to ROM area

Rev 2

Rev 2 Checkout

• Install jumper J2:1-2 since CPU is R65C02
• NOP tester - 6502 nop = 0xEA
  • Works
• Cut etch U1-39 in rear (removes PH2OUT from backplane)

• Add wire U1-39 to J2-3 (PH2OUT/VPB on VPB output)

Rev 2 Changes

• Add pull-up resistor on ABORT* line (U1-3)
• Add pull-up resistor on BE line (U1-36)

Rev 1

• Install jumper J2:1-2 if CPU is not a WDC 65C02 or WDC 65C816
• If WDC 65C02 or WDC 65C816 is used:
  • Add pull-up resistor on ABORT* line (U1-3)
  • Add pull-up resistor on BE line (U1-36)

Assembly Sheet

Rev 2

• Interactive BOM

Rev 1

• Interactive BOM