DIO48S/AT-P Manual
Page 6-6
Manual 00650-526-1
Change-of-state Interrupts
At power-up or Reset, a register that enables change-of-state interrupts is set to zero. This
enables all inputs to generate change-of-state interrupts. During initialization this register should
be programmed to prevent interrupt generation by inputs that you do not want to cause
change-of-state interrupts or by ports that are programmed as outputs. To program this
Change-of-State-Interrupt-Enable Register, write to it at Base AB. Data bits D0 through
D5 control ports A, B, and C of the 8255 PPIs as shown in Table 6-3.
Bit
Port Controlled
D0
Group 0, Port A
D1
Group 0, Port B
D2
Group 0, Port C
D3
Group 1, Port A
D4
Group 1, Port B
D5
Group 1, Port C
Table 6-3:
Change-of-state-interrupt-enable Register
Writing a "one" disables the port; writing a "zero" enables it. This register is latched.
To clear the latch, write anything at Base AF.
Summary of Contents for DIO48S/AT-P Series
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