Arcom SC88T, Техническое руководство

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Section 7. Using the SC88T
Because the SC88T can be configured in so many different ways, it is difficult to
make any general recommendation about using it, mainly because the software
will determine how it is used. There are two obvious situations where it can be
employed, and a summary of them may suggest other possibilities.
As a target system
Here the SC88T runs software created on another computer, which is
transferred either by blowing an EPROM or by downloading machine-code into
RAM. A useful approach is to have a machine-code monitor in the EPROM
socket, so that the code can be debugged.
If you want to start from scratch the following notes may help.
The chip-select for EPROM (UCS) should be set up first, so that you can jump to
the start of EPROM and then continue initialising.
The LCS is required before any stack or memory operations are done with the
on-board memory.
The peripheral chip-selects must be programmed to allow access to the on-
board SCC.
Timers 0 and 1 may be programmed to produce a bus timeout function. The
input to T0 is the bus driver enable line; T0 output is wired to T1 input, and T1
output going low will take the CPU out of the wait-state. For this to happen it is
necessary to set T0 up as a free-running timer which is stopped by the active-
low bus-driver enable signal: T1 must be set up to be retriggered by pulses on
its input (which is connected to T0 output). If T1 then fails to be retriggered to
T0 it will time out. It can also generate an interrupt when it times out so that the
CPU is aware that a timeout has occurred.
The SCC requires some initialisation code, and it is strongly recommended that
you obtain the SCC Technical Manual before doing anything unusual.
If 80188 instructions are used in ‘test and set’ operations for communication
between processors on the bus, they should be prefixed with the LOCK prefix.
This will prevent the bus request from going away until the instruction is
complete.
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J90 SC88T 2192-08819-000-000