SIMPLE-6802

Features

• 68B02 CPU
  • 1.8432 MHz clock
  • MC6802 is fully compatible with MC6800 but without messy two-phase clocking
• 32KB SRAM
• 16KB EPROM/EEPROM
  • 16KB reserved
  • 8KB (28C64 parts can be used)
• 68B50 Serial Port (ACIA)
  • RS-232 port
  • Header for FTDI
  • 115,200 baud
• Reset switch with optional Power Supervisor
• 95x95mm card
• (4) 6-32 mounting holes

Memory Map

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

Chipset

• 68B02P
• MC68B50CP
• HM62256BLP-7 32KB SRAM
• SST27SF256-70-3C-PGE EPROM

Design

• CPU

• EPROM

• SRAM

• ACIA

• FTDI

Headers / Connectors

J1 - RS-232 Serial

• DB-9 Male
• Pinout

1. N/C
2. Receive
3. Transmit
4. Loop to pin 6
5. GND
6. Loop to pin 4
7. RTS
8. N/C
9. N/C

J2 / J5 - EPROM/EEPROM Select Jumpers

27512	27256	27128	2764	28C64	PIN		PIN	2764	28C64	27128	27256	27512
A15	VPP	VPP	VPP	N/C	1 (J2)		28	VCC	VCC	VCC	VCC	VCC
A12	A12	A12	A12	A12	2		27 (J5)	PGM	WE*	PGM	A14	A14
A7	A7	A7	A7	A7	3		26	A13	N/C	A13	A13	A13
A6	A6	A6	A6	A6	4		25	A8	A8		A8	A8
A5	A5	A5	A5	A5	5		24	A9	A9		A9	A9
A4	A4	A4	A4	A4	6		23	A11	A11		A11	A11
A3	A3	A3	A3	A3	7		22	OE*	OE*		OE*	OE*
A2	A2	A2	A2	A2	8		21	A10	A10		A10	A10
A1	A1	A1	A1	A1	9		20	CE*	CE*		CE*	CE*
A0	A0	A0	A0	A0	10		19	D7	D7		D7	D7
D0	D0	D0	D0	D0	11		18	D6	D6		D6	D6
D1	D1	D1	D1	D1	12		17	D5	D5		D5	D5
D2	D2	D2	D2	D2	13		16	D4	D4		D4	D4
GND	GND	GND	GND	GND	14		15	D3	D3		D3	D3

J3 - FTDI / TTL Serial

• Requires a FTDI cross-over cable

1. GND
2. RTS* (out)
3. +5V
4. Receive (in)
5. Transmit (out)
6. N/C

J4 - 5V Power

• 2x4 header

First Unit Checkout

Install Sockets

• Machined pin sockets

Power

• Install 2x4 at J4
• Power card via J4 with 5V
• Check power pins on parts

Software

SmithBUG Builds for SIMPLE-MC6802 CPU Card

• SIMPLE-6802 Wiki Page
• Pre-built software
  • 4KB build
  • 8KB build
  • 16KB build

Building Code

• Uses a68 assembler
  • Command line makes S-Record output
• Use srec_cat to shift from EPROM absolute addresses to 0x0000 as HEX file

4KB Build

A68 SMITHBUG_SIMPLE-6802_F000.ASM -l SMITHBUG_SIMPLE-6802_F000.LST -s SMITHBUG_SIMPLE-6802_F000.S
srec_cat SMITHBUG_SIMPLE-6802_F000.s -offset - -minimum-addr SMITHBUG_SIMPLE-6802_F000.s -o smithbug_F000.hex -Intel

8KB Build

A68 SMITHBUG_SIMPLE-6802_E000.ASM -l SMITHBUG_SIMPLE-6802_E000.LST -s SMITHBUG_SIMPLE-6802_E000.S
srec_cat SMITHBUG_SIMPLE-6802_E000.s -offset - -minimum-addr SMITHBUG_SIMPLE-6802_E000.s -o smithbug_E000.hex -Intel

16KB Build

• Used with 27SF256 parts
  • 2nd half unused

A68 SMITHBUG_SIMPLE-6802_C000.ASM -l SMITHBUG_SIMPLE-6802_C000.LST -s SMITHBUG_SIMPLE-6802_C000.S
srec_cat SMITHBUG_SIMPLE-6802_C000.s -offset - -minimum-addr SMITHBUG_SIMPLE-6802_C000.s -o smithbug_C000.hex -Intel

SmithBUG Commands

;	M	MOVE MEMORY
;	E	CHANGE MEMORY
;	G	GO TO PROGRAM
;	R	PRINT
;	T	TRACE PROGRAM
;	@	ASCII CONVERSION
;	H	PRINTER ON
;	V	VIEW MEMORY
;	I	FILL MEMORY
;	J	JUMP TO TARGET PROGRAM
;	F	FIND 
;	Q	HARDWARE LOCATION
;	D	DISASSEMBLE CODE
;	K	CONTINUE AFTER BREAK
;	1	BREAKPOINT ONE
;	2	BREAKPOINT TWO
;	&	S1 LOAD PROGRAM
;	*	HARDWARE LOCATION (TBA)
;	O	ECHO ON
;	N	ECHO OFF

Performance

• TeraTerm settings

• Test software

10 FOR I =1 TO 10000
20 PRINT I
30 NEXT I

• Time ~ secs

Mechanicals

Assembly Sheet

SIMPLE-6802 Rev 1 Assembly Sheet