HD6417750 Datasheet, PDF (785/1039 Pages) Renesas Technology Corp – SuperH RISC engine

Figure 18.2 shows a block diagram of the 4-bit general-purpose I/O port.
PBnPUP
PORTEN
Pull-up resistor
Internal bus
Dn output data
0
DQ
1
PDTRW C
BCK
0
DnDIR
1
PBnIO
0
Data input strobe
1
C
QD
Dn input data
Port 19 (input/
output)/D51
to
Port 16 (input/
output)/D48
BCK
PORTEN
PBnPuP
DnDIR
PBnIO
0: Port not available
0: Pull-up
0: Input
0: Input
1: Port available
1: Pull-up off
1: Output
1: Output
Figure 18.2 4-Bit Port
Rev. 6.0, 07/02, page 733 of 986