EnterMice
Joysticks & PS/2 Mouse Interface
for Enterprise 64 & 128 computer
Contents
Introduction
This complex interface has been designed for the Enterprise 64/128 series computer. The achievement is the culmination of six months of work of a multidisciplinary Polish developer known on relevant forums as Pear.
The main goal of the adapter is to allow the use of cheap and widely available PS/2 mice on the Enterprise computer. In addition, it enables direct connection of two joysticks in Atari standard without additional adapters.
EnterMice is based on solutions used in the BoxSoft mouse interface, which supports the Neos mouse(MSX protocol).
One of the EnterMice operating modes is fully compatible with the old BoxSoft mouse interface. An other operating mode converts the mouse movement to joystick pulsations.
A little story about Enterprise and mice
Enhancing the Enterprise 128 with mouse control is not a new and eccentric idea of a geekish retro-computing group, it was already planned by the original EP designers. The problem was that the task was relegated to Aztec Software Ltd, a modest English company that came up with a disappointing job; for two main reasons: first, the product was ugly, nothing near the rounded shape of the Enterprise. Secondly, it was not an adequate mouse as it relied on emulated joystick movement. Also at that time Enterprise Computing Ltd. was disappearing.
But the user base in the United Kingdom remained very active in the years following. Little companies were founded by Enterprise enthusiasts. New products were offered: memory expansions, customized cables, games, utilities, Spectrum emulators, an IDE controller, Eprom, motherboard expansions, serial modems and so on.
The most prolific company was Boxsoft, founded by developer Tim Box. Boxsoft offered most of the products listed above. Bundled with a paint program called Paintbox, they marketed an adapter plus a Neos mouse with a driver included. The Neos, internally a MSX mouse, had already been successfully adapted to other 8-bit computers like the Commodore 64.
At that time only a few 8-bit computers had a working mouse with some form of GUI. It was very difficult to sell something new of unknown use and not completely integrated on the computer. Seen from today's perspective, the advantage of navigating operating systems and applications with a mouse is obvious, its convenience being realized instantly when the mouse stops working...
After all, only about a hundred of the Paintbox bundles were sold.
The Paintbox program arrived to Hungary separately. Hungarians bought Enterprise computers knowing that they came from the UK., but not much more. When all the Enterprise 128s were sold, the user base was abandoned as in the country of origin. Once again, new companies surfaced offering new products. Then a company named "A studio" began to manufacture and sell the Boxsoft items, camouflaging them as their own products. One of the programs was a Paintbox version without the mouse option. It still needed the driver, but a crippled version. At the east side of the Iron Curtain nobody ever heard of the Neos mouse.
Later, in Hungary, a serial card expansion for the Enterprise was realized, thanks to the genius of a team of Hungarian developers: Gyula Mészáros for the hardware, and László Haluska (HSOFT) for the software part. HSOFT took the crippled "A studio" mouse driver and modified it to suit the serial interface with a Mouse Systems mouse and later they supplied a built-in driver for the EPDOS 2.x operating system.
This is ancient history, but in recent years with WWW, Internet and globalization, some of the old artefacts Boxsoft+Neos emerged and all pieces of the puzzle began to fit. At last, the old promises (seen on Enterprise Computers Ltd. advertisments) of a real proprietary Enterprise mouse interface turned a reality.
The new Entermice interface presented here is based on the work of the Boxsoft team, but adapted to recent times, supporting new options. (It is a miracle what Tim Box achieved with only a few logical gates and diodes back then). As for the hardware, the driver was very well written by D. Rabson, Andrew Fitter and Andrew Richards. With minor modifications, the same driver will be used with the Entermice adapter.)
The principal problem interfacing the Enterprise is that connectors and signals are far from being a joystick-mouse standard. Little edge connectors that can be accidentally plugged upside down, commons pulled to +5v for the buttons when normally zero volt is used, lack of protection of the return of the signal when two or more buttons are pressed, no way to send information or state to the controller, and probably some more issues.
Now what Boxsoft pulled off with common, cheap components, has been redesigned and improved with two programmable chips and other modern components. One of the chips (a Xilinx) is in charge of the pinout and signal conversion to the Atari standard game port connectors. The original Boxsoft interface defined/standardized the first controller port only that was used to connect the Neos mouse or a standard joystick (but not both at the same time). In the present project two joystick ports have been provided and they don't interfere with the mouse port.
The Neos/MSX mouse is not widely found today so, a PS/2 to MSX conversion adapter has been implemented. It is driven by a powerful 12 MHz Atmel AT89C4051, able to adapt itself to the frequency of the Z80 processor installed on the Enterprise. With this chip and the proper coding it has inside, the Entermice can work on a 4 MHz EP or a supercharged 10 MHz one the same way.
Also, the mouse reading protocol has been expanded following Prodatron and NYYRIKKI's new extended MSX protocol so it can send information about five buttons on a wheel mouse, if present. It will soon be completely compatible with SymbOS (actually only in Boxsoft mode, see the features section about how to set this mode).
General description
Important
Do not connect the interface to the computer when the power is on !
If when you connect the interface your computer does not start up properly or behaves abnormally, it must be switched off immediately !
Check whether the interface is connected correctly and try again.
Mouse and joysticks can be connected and disconnected while the computer is power on, but this is not recommended. It is safer to perform any connection with the power disconnected.
Connecting to a computer
The interface board should be connected at the same time to 3 edge connectors on the back of your Enterprise: Control 1, Control 2 and Serial.
It can be inserted only one way, but the contact pins might not seat centered on the fingers of the edge connectors. If so, the contact might be unstable and the computer and/or the interface may not work properly.
Properly connected, the interface works right after turning on the power.
After turning on, a self-test is performed, during which both red and green LEDs will flash 3 times (regardless of the state of dip-switch 3).
Features
The interface can operate in several modes. To configure it, a five sectional dip-switch is provided.
The configuration settings can be changed during operation of the interface. You do not have to restart your computer.
Below is the description of all possible settings.
DS1 | DS2 | Work mode |
---|---|---|
ON | ON | EnterMice native mouse mode |
OFF | ON | BoxSoft compatible mouse mode |
OFF | OFF | EnterMice joystick mode (Movement made to the mouse is redirected to the input of Joystick 1, and that port is disabled) |
ON | OFF | not used (in fact EnterMice as joystick on KB K column) |
Joystick 2 always works the same way, regardless of the interface operating mode being selected.
DS3 | LED status |
---|---|
OFF | LED status disabled |
ON | LED status enabled |
Joystick emulation mode configuration
DS4 | Sensitivity |
---|---|
OFF | Normal |
ON | High |
DS5 | Diagonal correction |
---|---|
OFF | Disable |
ON | Enable |
Diagonal correction improves the precision of joystick simulation on diagonal movements, at the expense of a slight decrease in speed.
Troubleshooting
Keyboard issue
During the creation of the EnterMice, a fairly serious error in the design of the Enterprise was casually discovered.
It stays totally unnoticed if nothing is connected to the ports Control 1 and Control 2. However, the EnterMice uses them...
The issue is about interferences on KB0..KB9 ports from keyboard, that are also utilised by the control ports.
If only one key is pressed at the keyboard, then nothing wrong happens (see figure 1).
However, if you press two keys in the same column simultaneously, the signal from the selected line will be transferred to the line of the second key as well(figure 2).
The Enterprise lacks blocking return diodes to separate the rows of the keyboard!
Electrically nothing will happen (the LS145 decoder inside the computer has open collector outputs), but reading from the external ports Control 1 and Control 2 causes errors.
In order to eliminate the cause, diodes should be added to each row of keys on the Enterprise, to avoid that pressing more than one key does causes "collisions" (figure 3).
Pear has prepared a draft of a PCB to fix it , but it has not been tested yet. In the meanwhile, in order to avoid errors, the keyboard should not be operated while joysticks or mouse are in use.
Microsoft Optical Mouse
The PS/2 Microsoft Optical Mouse is a special case. It should be only connected inserted on its original Microsoft USB to PS/2 converter. It will work with EnterMice if connected before power on, but in its case, you can not use the hot-plug feature.
Entermice can be forced to recognise the Microsoft mouse during operation, you only need to momentarily short the RESET pin-header on the interface (it resets only the interface, not the computer).
Technical specification
Joystick port pinout
pin | signal |
---|---|
1 | Up |
2 | Down |
3 | Left |
4 | Right |
5 | Fire 3 |
6 | Fire 1 |
7 | +5 V |
8 | GND |
9 | Fire 2 |
Control Map
J column (bit 0) | K column (bit 1) | L column (bit 2) | |||||
---|---|---|---|---|---|---|---|
JM=0* | JM=1* | JM=0 | JM=1 | JM=0 | JM=1 | ||
Control 1 | Row 0 Fire | Joy 1 Fire 1 | Mice Left Btn | Mice Left Btn or Joy 1 Fire 2* | Joy 1 Fire 2 | Mice Right Btn or Joy 1 Fire 3* | |
Row 1 Up | Joy 1 Up | Mice D0 | Mice D0 | spare | spare | spare | |
Row 2 Down | Joy 1 Down | Mice D1 | Mice D1 | spare | spare | spare | |
Row 3 Left | Joy 1 Left | Mice D2 | Mice D2 | spare | spare | spare | |
Row 4 Right | Joy 1 Right | Mice D3 | Mice D3 | spare | spare | spare | |
Control 2 | Row 5 Fire | Joy 2 Fire 1 | Joy 2 Fire 2 | Joy 2 Fire 3 | |||
Row 6 Up | Joy 2 Up | spare | spare | spare | spare | ||
Row 7 Down | Joy 2 Down | spare | spare | spare | spare | ||
Row 8 Left | Joy 2 Left | spare | spare | spare | spare | ||
Row 9 Right | Joy 2 Right | spare | spare | spare | spare |
* Mouse buttons have higher priority * JM=0 (DS1 ON) native EnterMice mouse mode JM=1 (DS1 OFF) joystick emulation & BoxSoft compatible mode
Sega twister
for connect the Sega six-button pad
Sega Six Button Controller Hardware Info
Interface Protocol of SEGA MegaDrive's 6-Button-Controller
pin | Select = Low | Select = High | Select = pulse-3 |
---|---|---|---|
1 | Up | Up | Button Z |
2 | Down | Down | Button Y |
3 | GND | Left | Button X |
4 | GND | Right | not used |
5 | +5V | ||
6 | Button A | Button B | not used |
7 | Select | ||
8 | GND | ||
9 | Start | Button C | not used |
Information for developers
EnterMice timings
The firmware of EnterMice is optimized for the cyclic reading with 50 Hz frequency (video IRQ).
Default reading cycle | 20 ms |
Waiting time to perform self-test the PS/2 mouse (timeout) | ca. 2000 ms |
Time of collecting the PS/2 mouse data | max. 12 ms |
Time from change state of RTS signal to issue data (nibble) for reading | 25 μs |
Standby time for the next reading (counting from data issue) | 14 μs |
Time from read the last nibble of data to reset the nibble counter (timeout)* | 1500 μs |
Default mouse polling time in joystick emulation mode | 30 ms |
Mouse polling time in joystick emulation mode when mouse doesn't move (minimize polling delay) | 12,5 ms |
* After this time is performed another mouse data polling.
Data buffer
Data buffer in EnterMice has a size of 16 bytes.
Currently is used only a half. The remainder may be used in the future.
Byte | High nibble | Low nibble | Content | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | ||||
0 | X value | signed int (positive is moved left) | BoxSoft protocol | |||||||||
1 | Y value | signed int (positive is moved up) | ||||||||||
2 | 0 | 0 | 0 | 1 | 0 | Btn5 | Btn4 | Btn3 | Protocol identification & buttons 3,4,5 state | Extended MSX protocol | ||
3 | Horizontal wheel* | Z value | signed int (positive is wheel moved up) | |||||||||
4 | ExCnt | Mouse ID | Extra bytes available to read (include this) & PS/2 mouse ID | EnterMice extension protocol | ||||||||
5 | Hw ver. mj. | Hw ver. mn. | Hardware version (major.minor) | |||||||||
6 | Fw ver. mj. | Fw ver. mn. | Firmware version (major.minor) | |||||||||
7 | Device ID | EnterMice ID is 5Dh |
* not implemented yet, now all 8 bits is a Z value
You do not need to read all the data from the buffer.
Reading can be interrupted at any time. There will be the timeout and interface performs another read data from mice, then once again be ready to send data.
Last state of RTS signal also not matter. EnterMice reacts to the change state, not on the signal level.
Mouse reading
; Here begin the Neos mouse reading | ||
ld hl,X_REL | ; first byte | |
ld a,2 | ; RTS low | |
out (0B7h),a | ||
ld b,8 | ; long delay | |
call WAIT | ||
call READ_4BIT | ; read four higher bits | |
rld | ; push them in (HL) | |
xor a | ; RTS high | |
out (0B7h),a | ||
ld b,5 | ; short delay | |
call WAIT | ||
call READ_4BIT | ; read four lower bits | |
rld | ; push them in (HL) | |
ld hl,Y_REL | ; second byte | |
ld a,2 | ; RTS low | |
out (0B7h),a | ||
ld b,5 | ; short delay | |
call WAIT | ||
call READ_4BIT | ; read four higher bits | |
rld | ; push them in (HL) | |
xor a | ; RTS high | |
out (0B7h),a | ||
ld b,5 | ; short delay | |
call WAIT | ||
call READ_4BIT | ; read four lower bits | |
rld | ; push them in (HL) | |
;<======Here will be added the future Wheel and three spare buttons reading. SECOND TENTATIVE | ||
ld hl,SW_Z_STATUS | ||
ld a,2 | ; RTS low | |
out (0B7h),a | ||
ld b,5 | ; short delay | |
call WAIT | ||
call READ_4BIT | ; read four higher bits | |
and 15 | ||
cp 1 | ; IF THIS NIBBLE=0001 THEN THE MOUSE IS IN EXTENDED PROTOCOL | |
jr z,CONTINUE_READ | ||
xor a | ; RTS high | |
out (0B7h),a | ;IGNORE THAT NIBBLE | |
ld (hl),0 | ; we don't need old values | |
jr STOP_READ | ||
CONTINUE_READ: | ||
xor a | ; RTS high | |
out (0B7h),a | ||
ld b,5 | ; short delay | |
call WAIT | ||
call READ_4BIT | ; read four higher bits, the three lower bits are the buttons. They come ready to store | |
push af | ; push them in stack. they are in the lower nibble. | |
ld a,(hl) | ; | |
push af | ;save the Z counter for later. | |
ld a,2 | ; RTS low | |
out (0B7h),a | ||
ld b,5 | ; short delay | |
call WAIT | ||
call READ_4BIT | ; read four bits | |
rld | ;we need z displacement in 8 bit | |
xor a | ; RTS high | |
out (0B7h),a | ||
ld b,5 | ; short delay | |
call WAIT | ||
call READ_4BIT | ; read four lower bits. Z displacement | |
rld | ; push them in (HL) ;NOW WE HAVE Z displacement in (hl) | |
pop af | ; restored Z counter to "a", but we have garbage on high nibble | |
and 00Fh | ||
bit 3,a | ||
jr z,SIGN_DONE | ||
or 0F0h | ||
SIGN_DONE: | ; now we have the sign extended to 8 bits on "a" | |
add a,(hl) | ||
cp 128 | ; positive or negative? | |
jr c,POSITIVE | ||
cp 248 | ; lower than -8? | |
jr nc,FINISHED | ; | |
ld a,248 | ; -8 is the bottom | |
jr FINISHED | ||
POSITIVE: | ||
cp 8 | ; higher than 7? | |
jr c,FINISHED | ||
ld a,7 | ; 7 is the top | |
FINISHED: | ; the excess of 7 or -8 has been wiped | |
ld c,a | ; save Z addition on c | |
pop af | ; retrieve the buttons status. They are now on first nibble of a | |
rld | ; buttons stored | |
ld a,c | ; we only need the first nibble of Z counter addition | |
rld | ; the spare buttons status and the Z counter are now in SW_Z_STATUS | |
STOP_READ: | ||
xor a | ; recall buttons on row 0 | |
out (0B5h),a | ||
in a,(0B6h) | ; read Mouse buttons | |
and 7 | ; mask | |
xor 7 | ; flip them all as on Enterprise a pressed key is 1 and released 0 | |
rl (hl) | ; Get ready the bit 7 of "hl" register pair. Inside is SW_Z_STATUS, variable number 190 | |
srl a | ; This is the very FIRST "srl a". The button status is now in the carry flag | |
; secondary button of Boxsoft is read on J column. Primary button of Entermice is read on K column | ||
push af | ||
ld a,(INPUT_DEVICE) | ||
cp 3 | ; Boxsoft interface mode buttons | |
jr nz,L_BUTTON | ||
pop af | ; We need the value of "a" and "f" registers. Carry flag still stores the value of secondary button | |
rr (hl) | ; secondary button goes to bit 7 of SW_Z_STATUS, variable number 190 | |
srl a | ; Primary button of Boxsoft is on J column. This is the second "srl a" | |
JR MAIN_BUTTON | ||
L_BUTTON: | ; Entermice interface mode buttons | |
pop af | ; retrieve the value of register "a". "f" is disposable, soon we will load the button on carry flag | |
push af | ; I still will need later the register "a" value | |
srl a | ; two "srl a" because the secondary button of Entermice is read on L column | |
srl a | ; the proper button status is now in the carry flag | |
rr (hl) | ; secondary button goes to bit 7 of SW_Z_STATUS, variable number 190 | |
pop af | ; retrieve the value of register "a" just after the FIRST "srl a" | |
MAIN_BUTTON: | ||
and 1 | ||
ld (FIRE_STATUS),a | ; EXOS Variable 188. K column if Boxsoft or L column if Entermice | |
call sub_C3A6 | ; this is the "corrections and drawing" routine where the "velocity" 1.1 modification was made | |
ld a,(X_REL) | ||
ld c,a | ||
ld a,(Y_REL) | ||
or c | ||
ret | ||
WAIT: | ||
nop | ||
nop | ||
nop | ||
dec b | ||
jr nz,WAIT | ||
ret | ||
READ_4BIT: | ; I split the routine in two to not put more processor time | |
ld b,4 | ||
ld d,0 | ||
ld a,(INPUT_DEVICE) | ||
cp 3 | ||
jr z,L_COLUMN | ||
K_COLUMN: | ||
ld a,b | ||
;inc c | ; this is not necessary | |
out (0B5h),a | ||
in a,(0B6h) | ||
;ld c,a | ; this is not necessary | |
rra | ; data read from K column | |
rra | ||
rl d | ||
djnz K_COLUMN | ||
jr CONTINUE | ||
L_COLUMN: | ||
ld a,b | ||
;inc c | ; this is not necessary | |
out (0B5h),a | ||
in a,(0B6h) | ||
;ld c,a | ; this is not necessary | |
rra | ; data read from L column | |
rl d | ||
djnz L_COLUMN | ||
CONTINUE: | ||
ld a,d | ||
ret |