Reset, warm boot, cold boot (DS-R)
Additionally to the reset switch it is possible to perform a reset by software through pressing
DS-R key combination. Used in instance 1-7 the current instance will be restarted. Pressing the
reset switch will do a change to instance 0 but only with a warm boot. There are circumstances
where a cold start is required which can be forced by pressing DS-R in instance 0 which will
reset all other instances as well.
A short interrupt of the power supply results in a warm start only. There maybe situations
where an instance may hang or crashed and pressing DS-R for a single instance won't work
because the display file is corrupt for example. In this case the instance 0 doesn't get control
back and all double-shift commands won't work anymore. It is recommended to press the
reset key followed by a DS-R combination in instance 0 to solve this.
Power Mode (DS-P)
The default clock speed is 3.25 MHz for ZX80 or ZX81 hardware.
The effective clock speed is
much lower with approx. 0.81
MHz because the display
routines require much time of
the cpu and the user program
is interrupted many times.
The ZXmore can compensate
this disadvantage by doubling
the clock speed outside the
video routines to 6.5 MHz. The
resulting speed increases a bit
more than double due to some
more hardware optimizations.
The imaged screenshot shows
the unofficial benchmark for
ZX81 systems and the speed
increase with ZXmaster in
version 0.9
Sometimes a program may not work correctly or maybe too fast. If this annoying the speed
can be changed to 3.25 MHz only which is handled per instance. It is possible to active a fast
and a slow instance for example. Every DS-P key combination changes speed in current
instance from low to fast or fast to low consecutively.
Compatibility mode (DS-C)
The firmware ZXmaster supports the smooth operation of ZX81 instances. There may be
situations where a program used with ZX81 does not behave in the same way as on real
hardware. The compatibility mode may be chosen by the user in these cases to get a most
compatible environment by the price of losing control through ZXmaster which can be
reactivated by pressing the reset switch when needed. Especially HRG programs executed in
version 0.9 may not display an image as the video handling is different.
Whenever programs do crash or not behave in the same way as expected there may be a good
choice for the compatibility mode for these programs to run better. If the speed should be
decreased or a program loaded via USB flash disk this can be done first and then pressing
DS-C after.
V1.9 - 06/2016
ZXmore & ZXmaster – user manual
page 8 from 29
