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
- Picture shows 3 MHz CPU
- Received 2 MHz CPU
- As received:
Oscillator
PLD
- ATF16V8B part
- TL866ii Plus Programmer
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
- 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
- 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
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
- 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 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
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
Mechanicals
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
- 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)
