
CHAPTER 2 PIN FUNCTIONS
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(ix) WRH (Write Strobe High Level Data) ··· output
This is a write strobe signal output pin for the high-order data in an external 16-bit data bus. Output
occurs during the write cycle, similar to DSTB.
(x)
RD (Read) ··· output
This is a read strobe signal output pin for an external 16-bit data bus. Output occurs during the read
cycle, similar to DSTB.
(10) P100 to P107 (Port 10) ··· 3-state I/O
Port 10 is an 8-bit I/O port in which input and output pins can be specified in 1-bit units.
P100 to P107 can function as I/O port pins, a real-time output port, address buses (A5 to A12) when memory is
expanded externally, and a key return input.
P100 to P107 can select normal output and N-ch open-drain output.
(a) Port mode
P100 to P107 can be set bit-wise as input or output pins according to the contents of the port 10 mode
register (PM10).
(b) Control mode
(i)
RTP0 to RTP7 (Real-time Port 0 to 7) ··· output
These pins comprise a real-time output port.
(ii)
A5 to A12 (Address 5 to 12) ··· output
These comprise the address bus that is used for external access. These pins operate as A5 to A12 bit
address output pins within a 22-bit address. The output changes in synchronization with the rising edge
of the clock in the T1 state of the bus cycle. When the timing sets the bus cycle as inactive, the
previous bus cycle’s address is retained.
(iii) KR0 to KR7 (Key Return 0 to 7) ... input
These are key return input pins. Their operations are specified by the key return mode register (KRM).
(11) P110 to P113 (Port 11) ··· 3-state I/O
Port 11 is a 4-bit I/O port in which input and output pins can be specified in 1-bit units.
(a) Port mode
P110 to P113 can be set bit-wise as inputs or outputs according to the contents of port 11 mode register
(PM11).
P110 to P113 can function as I/O port pins, address buses (A1 to A4) when memory is expanded externally,
and the control signal (WAIT) that inserts waits into the bus cycle.