----- Original Message -----
From: "Aleš Keprt" <a...@keprt.cz>
To: <sam-users@nvg.ntnu.no>
Sent: Sunday, April 08, 2012 12:53 AM
Subject: ASCD 0.98 (final) released
* Fixed minor incompatibility in kempston joystick emulation (top 3 bits were
set instead of reset)
This is problem:
- Part of ZX Spectrum games work only with original kempston joystick readable
also on port #DF (joystick port adressation is only A5=0 and all other adress
lines are ignored = joy port BIN xx0xxxxx ).
- exist more versions of kempston joystick interface and often is used models
with port adressation: BIN 000xxxxx or new interfaces use full adressation BIN
00011111.
- old joystick interfaces send joystick value only to data lines D0-D4. Bits
D5-D7 are not set or reset, but contain part of floating data bus (transparent
ula port #FF = videoram data). This three bith are readable always in log.1 only
if ula not read videoram data (in border area/after interrupt).
- modern joystick interfaces and some ZX emulators return always D7-D5 in log.0.
Some ZX games also work only if D7-D5 is 0. Also all games/software writed in ZX
basic need it.
Not exist any universal joystick standard, but often is used adressation: BIN
000xxxxx and joystick return always D7-D5 in log.0 and D4-D0=joy state. D5 can
be used for joystick fire 2 and D6 for joystick fire 3. This is best. Old
problematic ZX games exist also in fixed version for use with any joystick
interface. (see W.O.S.)
My idea: can you add joystick autofire emulation ? :-D
VELESOFT
