Hardware articles index > The ACF version 1

The ACF version 1

he idea- would it be possible to save and load Jupiter Ace Forth dictionaries and programs to some kind of disk system? There was the Jet-Disk interface developed by MPE in 1983, but with no information on how this worked or any photos we could not build one. Many other 8-bit 1980s home micros have IDE compact flash card (CF) interfaces made by fans of these old machines.

Edwin Blink had also being experimenting with building a CF card system that required very little or on extra hardware for his Sam Coupe computer. When I asked if such a device could be built for the Ace and agreed that we should do some experimenting with the Ace. A CF to IDE board would be utilised these are known as P11 IDE boards and can be found on eBay they are often used in embedded systems that use the CF cards as a storage place for data and the like, see P11 image below. The Ace Compact Flash interface (ACF) would be built using a small board connecting the Ace to the P11 board using a 2x20 IDE box header. Edwin started the ball rolling with the text file below.
ACF - Ace Compact Flash Interface v1.1

ACF Ports

Decimal Hex	Description

127	07F	Data Register
383	17F	Error
639	27F	Sector Count
985	37F	Sector
1151	47F	CylLo
1407	57F	CylHi
1663	67F	Head
1919	77F	Command

ACE Edge connector to CF-IDE adapter Wiring

Ace		IDE-pin Signal
D7		3	D7
D6		5	D6
D5		7	D5
D4		9	D4
D3		11	D3
D2		13	D2
D1		15	D1
D0		17	D0
/WR		23	/WR
/RD		25	/RD
A9		33	A1
A8		35	A0
A10    		36	A2
A7------>|--\___37	CS1 (TASK Registers)
5V		38	CS3 (Device control)
5V		20	5V 
0V		40	0V 
->|-	= 1N4148 Diode
-/\/\-	= 1KOhm Resistor


type 1919 IN . it should print 80 on the screen
The P11 CF to IDE
The P11 CF to IDE card also a 8Meg Cannon CF card. There are three jumpers on the card JP1 to set the power source from the IDE pin 20 or the disk drive type connector top right. We chose to pull the power from the Jupiter Ace via pin 20 of the IDE, setting the jumper to short 2-3. Jumper sets the supply voltage keep this +5V, short 1-2. Jumper 3 sets the card to slave or master. At this stage its set to master short 1-2. The are also three LEDs on the small board red for power, yellow CF card detect and green for read / writes to the CF card.
ACF 1 this one build by Edwin, as my one was not as neat and tidy!

ACF 1 powers up, P11 has power and detects the CF card.

Monitor shot with the first ACF test, IN 1919 . results in the value 80 being displayed

First test read the status register of the CF card with IN 1919 which puts the value of the port on the stack. The . (dot) prints the top value from the stack to the screen which was 80, meaning the card seems to have no problems and is waiting for a command. But at this stage that's all we have at this stage. After a few more tests we do find a problem that the address lines seem to be overloaded. The keyboard uses the address lines so maybe we need a buffer on the ACF Edwin suggests using a 74HCT244 and 74HCT245 and two decoupling capacitor. A re-think and we are back with ACF version 2.

Valid HTML 4.01 Transitional