The Small C Compiler for 6809 running on FLEX (CUG 221) has been ported to
MSDOS, and changed to allow creation of embedded target software. It supports
the ASxxx group of assemblers (CUG 292) available from the C users Group, as
well as the Motorola AS9 assembler.
A host of routines is supplied. These work with particular boards used by our
students. The system we have is,
6809 Processor card, 32k StaticRAM 0000 to 7FFF
Addresses 9000-93ff are port mapped to 000 to 3ff for PC
type boards
Addresses 8000 to 8fff are mapped to B0000 for PC
monochrome cards
On board ACIA, MC6850 at A000 (ControlReg) A001 (DataReg)
OnBoard EPROM or StaticRAM C000 to FFFF
The processor card drives an IBM-PC backplane with four expansion sockets,
thus can talk directly to standard PC cards. The routines for this board are
ACIA.H, MEMORY.H, STRINGS.H
Standard PC Serial Card (SERIAL.H)
Standard Hercs/Monochrome card (HERCS.H, PRINTER.H)
32bit Digital I/O card, plus 8 channel A/D (0808 chip). The mapping arrangment
of this board is,
Port 220h A/D Channel register
Port 221h A/D Data register
222h A/D End Of Conversion signal
223h Simple latched I/O
224h 8255 PPI Port A
225h 8255 PPI Port B
226h 8255 PPI Port C
227h Intel 8255 PPI control register
In conjunction with this board, a panel comprising,
1 x 7 segment display
1 x 8 LEDS
1 x 8 Digital Switches
1 x 16 hexidecimal keypad
is used to allow students to write software routines. (DIOBOARD.H, MCRDRV.H)
A magnetic card swipe reader attaches to port C of the DIOBoard.
The DIOBoards address is configurable via DIP, and the A/D convertor can be
- strapped for auto restart, EOC signal restarts ADC
- software polled via EOC bit status
- Interrupt driven, by staps which connect EOC to IRQ2 to IRQ7
The POD SOFTWARE is a simple board MC6821 which has a 40PIN DIP which plugs across the 6809 target processor. By writing to the MC6821 (which connects to DIOBoard) and setting certain pins, it is possible to alter the processor state (ie, RESET, HALT) and perform READ/WRITE cycles (by emulating bus cycles asserting pins mapped to processors pins in correct sequence).
All the available items are available from us at reasonable cost, eg, US funds
6809 processor card, assembled and tested (DS PCB) $ 80
DIO Card 32bit I/O, 8 channel A/D etc $ 80
DIO Panels, switches, leds, keymatrix, sevenseg $ 80
POD System with POD Software $100
We are also currently working on MC68000 and i8051 processor boards.
IF YOU RE-COMPILE THE SOURCE, USE A MEDIUM MEMORY MODEL!! AND TURN OFF