Mitsubishi Electric Apricot LS Pro, Hardware Technical Reference

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Memory and I/O Usage
Chapter 4
Chapter 6
Appendix A
Appendix C
Pr
eface
Chapter 4Chapter 5
5/8 LS PRO HARDWARE TECHNICAL REFERENCE
Port B
Write
operations
7 6 5 4 3 2 1 0
speaker gate
speaker data
enable parity check
enable I/O check
refresh detect
timer 2 output
I/O check
parity check
Bit 0 Setting this bit to 1 enables the timer 2 gate. Setting this bit to 0 disables
the timer 2 gate.
Bit 1 Setting this bit to 1 enables speaker data. This bit is set to 0 during a
system reset.
Bit 2 Setting this bit to 0 enables Parity check. This bit is set to 1 during a
system reset.
Bit 3 Setting this bit to 0 enables an I/O check. This bit is set to 1 during a
system reset.
Bits 4-7 Reserved
Read
operations
7 6 5 4 3 2 1 0
speaker gate
speaker data
enable parity check
enable I/O check
refresh detect
timer 2 output
I/O check
parity check
Bit 0 A read operation returns the result of the last write operation to this bit.
Bit 1 A read operation returns the result of the last write operation to this bit.
Bit 2 A read operation returns the result of the last write operation to this bit.
Bit 3 A read operation returns the result of the last write operation to this bit.
Bit 4 This bit toggles on each refresh request.
Bit 5 This bit reflects the condition of the timer 2 output latch.
Bit 6 This bit reflects the condition of the I/O check latch. If the bit is set to
1 an I/O check has occurred.
Bit 7 This bit reflects the condition of the Parity check latch. If the bit is set
to 1 a Parity check has occurred.