Port P5 (P54 To P50) (Large Current Port) - Philips CEM2100/00 Service Manual

5. I/O Ports

5.6 Port P5 (P54 to P50) (Large Current Port)

5.6 Port P5 (P54 to P50) (Large Current Port)
Port P5 is an 5-bit input/output port.
Port P5 is also used as an I
When used as an input port and I
During reset, the P5DR is initialized to "1".
P5 port output latch (P5DR) and P5 port terminal input (P5PRD) are located on their respective address.
When read the output latch data, the P5DR should be read. When read the terminal input data, the P5PRD register
should be read.
If a read instruction is executed for port P5, read data of bit 7 to 5 are unstable.
Data input (P5PRD)
Output latch read (P5DR)
Data output (P5DR)
Note: i = 4 to 0
P5DR
(0005H)
R/W
P5PRD
(000FH)
Read only
2
C Bus input/output.
2
C Bus input/output, the corresponding output latch (P5DR) should be set to "1".
STOP
OUTEN
Control output
Control input
7 6 5 4
P54
P54
D Q
Output latch
Figure 5-7 Port 5
3 2 1
P53 P52 P51
SDA
P53 P52 P51
Page 58
T5CL8
0
P50
(Initial value: ***1 1111)
SCL
P50
P5i