LB-65CXX-01

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LB-65CXX-01 P1090724-720px.jpg

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

LB-65CXX-01 CPU.PNG

  • 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)

R65C02 vs W65C02 w65c816 Pinout 800PX.png

VDA/VPA (65C816)
  • VDA/VDA
    • 00, Internal operation (invalid address bus)
    • 01, Valid Program Address
    • 10, Valid Data Address
    • 11, Opcode-fetch

Chip Set

LB 65C02 PARTS.jpg

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

SIMPLE-6502 P1090155-720px.jpg

Oscillator

LB-65CXX-01 OSC.PNG

PLD

LB-65CXX-01 PLS.PNG

PLD Listing

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

LB-65CXX-01 RES.PNG

Backplane connector

LB-65CXX-01 BKPL.PNG

Software

Assembly Language Development Toolchain

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
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

Simple Monitor 6502

  • SimpleMon6502.s - GitHub repo
  • Contains
    • ACIA init, read, write
    • Simplest commands mostly for function development
    • String functions
      • Read a string
      • Write a string (macro)
      • Write hex value as a string
  • Dump page (256-bytes) of memory

6502 Enhanced BASIC

?FRE(0)
 31956

Enhanced BASIC Bug Fixes

; Ibuffs can now be anywhere in RAM, ensure that the max length is < $80,
; the input buffer must not cross a page boundary and must not overlap with
; program RAM pages!

;Ibuffs            = IRQ_vec+$14
Ibuffs            = VEC_SV+$16
                              ; start of input buffer after IRQ/NMI code
Ibuffe            = Ibuffs+$47; end of input buffer
  • Boots to request memory size

EnhBASIC BOOT.PNG

  • Runs on card

EnhBASIC LOOP.PNG

OSI BASIC

  • LB-6502 GitHub
  • Create your own Version of Microsoft BASIC for 6502
  • Grant Searle's 6502 design
  • 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
    • Use srec_cat utility to convert the "bin" file to HEX or s19 (etc)
  • 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.
  • Having trouble running code

Programming References

6502 Instruction Set

Additional Tools

Mechanicals

LB-665CXX-01 REV2 MECHS.PNG

Checkout

Rev 3

PCB Updates

  • Add bulk electrolytic cap
  • Make PH2OUT on VPB backplane line (swap wth VDA)
  • 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
  • Add LED
    • 1.8K resistor from U2-17 to Ground
    • Wire U2-11 to U1-33 CPUD0

LB-65CXX-01 P1090727-720px.jpg

  • Cut etch U1-39 in rear (removes PH2OUT from backplane)

LB-6502 VPA Rework.PNG

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

LB-6502 VPB Rework.PNG

Rev 2 Changes

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

LB-65CXX-01 CPU Rev2.PNG

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

Rev 1