Electronics America 8-Bit Single-Chip Microcontrollers User's Manual

145
CHAPTER 6 PORT FUNCTIONS
P-ch
WR PM
WR PORT
RD
WR
PUO
V DD
Selector
PUO6
Output Latch
(P64 to P67)
PM64-PM67
Internal bus
P64/RD,
P65/WR,
P66/WAIT,
P67/ASTB
WR PM
WR PORT
RD
V
DD
Selector
Output Latch
(P60 to P63)
PM60-PM63
Internal bus
P60-P63
Mask Option Resistor
Mask ROM products
only. PROM versions
have no pull-up resistor.
Figure 6-13. P60 to P63 Block Diagram
PM : Port mode register
RD : Port 6 read signal
WR : Port 6 write signal
Figure 6-14. P64 to P67 Block Diagram
PUO : Pull-up resistor option register
PM : Port mode register
RD : Port 6 read signal
WR : Port 6 write signal