Overview Of I/O Ports - Fujitsu Semiconductor Controller MB89950/950A Hardware Manual

CHAPTER 4 I/O PORTS
4.1

Overview of I/O Ports

The I/O ports consist of five ports (33 pins) including N-ch open-drain and CMOS
general-purpose I/O ports (parallel I/O ports).
The ports also serve as peripherals (I/O pins of peripheral functions).
I I/O port functions
The functions of the I/O ports are to output data from the CPU via the I/O pins and to fetch signals input to
the I/O pins into the CPU. Input and output are performed via the port data registers (PDR). Also, for
certain ports the direction of each I/O pin can be individually set to either input or output for each bit by the
port data direction register (DDR).
The following lists the functions of each port and the peripheral with which the ports also serve as.
• Port 0: General-purpose N-ch open-drain I/O port. Also serves as LCD segment driver pins.
• Port 1: General-purpose N-ch open-drain I/O port. Also serves as LCD segment driver pins.
• Port 2: General-purpose N-ch open-drain I/O port. Also serves as LCD segment driver pins.
• Port 3: General-purpose N-ch open-drain I/O port. Also serves as LCD bias pins.
• Port 4: General-purpose CMOS I/O port. Also serves as other peripheral I/O pins.
Table 4.1-1 "Port function" lists the functions of each port and Table 4.1-2 "Port registers" lists the
registers for each port.
Table 4.1-1 Port function
Input
Port Pin name
type
P00/SEG20
Port 0 to
P07/SEG27
P10/SEG28
Port 1 to
P17/SEG35
CMOS
P20/SEG36
Port 2 to
P25/SEG41
P30
Port 3 to
P33/V2
P40 CMOS
to (resource:
Port 4
P46/INT0 hysteresis)
70
Output
Function
type
General-purpose I/O port
Segment driver output
General-purpose I/O port
Segment driver output
N-ch
open-drain
General-purpose I/O port
Segment driver output
General-purpose I/O port
LCD bias
CMOS General-purpose I/O port
(push-pull
Peripherals
option)
Bit 7 Bit 6 Bit 5 Bit 4
P07 P06 P05 P04
SEG27 SEG26 SEG25 SEG24 SEG23 SEG22 SEG21 SEG20
P17 P16 P15 P14
SEG35 SEG34 SEG33 SEG32 SEG31 SEG30 SEG29 SEG28
-- -- P25 P24
-- -- SEG41 SEG40 SEG39 SEG38 SEG37 SEG36
-- -- -- --
-- -- -- --
-- P46 P45 P44
-- INT0 SCK SO
Bit 3 Bit 2 Bit 1 Bit 0
P03 P02 P01 P00
P13 P12 P11 P10
P23 P22 P21 P20
P33 P32 P31 P30
V2 V1 -- --
P43 P42 P41 P40
PWC/
SI PWM --
INT1