Real Time Devices AD1200 User Manual page 115

82C5sA
oor?notronD
251256-7
Flgure 7. Blt Set/Reset Format
Interrupt Control Functlons
When the 82C55A is programmed to operate in
mode 1 or mode 2, control iignats are provided that
can be used as interrupt requ€st inputs to the GpU.
The interrupt request signals, generated from port C,
can be inhibited or enabled by setting or resetting
the associated INTE flip-flop, using the bit set/reset
function of port C.
This function allows the Programmer to disallow or
allow a specific l/O device to intem.rpt the CPU with-
out atfecting any other device in the interrupt struc-
ture.
INTE flip-flop definition:
(BIT-SET)-INTE is SET-lnterrupt enabte
(BIT-RESETFINTE is RESET-lnterrupt disabte
Note:
All Mask flip-flops are automatically reset during
mode selection and device Reset.
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