t6020m ATMEL Corporation, t6020m Datasheet - Page 24

• Manufacturer Part Number: t6020m
• Description: Low-current Microcontroller For Watchdog Function
• Manufacturer: ATMEL Corporation

3.2.3
The bidirectional Port 4 is both a bitwise configurable I/O
port and provides the external pins for the Timer 2, SSI
and the voltage monitor input (VMI). As a normal port,
it performs in exactly the same way as bidirectional Port 2
(see figure 22). Two additional multiplexes allow data
and port direction control to be passed over to other inter-
nal modules (Timer 2, VM or SSI). The I/O-pins for SC
Port 4 Data Register (P4DAT)
Port 4 Control Register (P4CR) Byte Write
P4xM2, P4xM1 – Port 4x Interrupt mode/direction code
T6020M
24 (54)
P4DAT
P4CR
Master reset
Bidirectional Port 4
PDir
I/O Bus
POut
I/O Bus
I/O Bus
Intx
PIn
First write cycle
Second write cycle
PxDATy
PxCRy
D
D
P4DAT3
Bit 3
S
S
Q
Q
(Direction)
PxMRy
P4DAT2
Bit 2
P41M2
P43M2
Bit 3
Bit 7
Figure 22. Bidirectional Port 4
P4DAT1
Bit 1
P41M1
P43M1
Bit 2
Bit 6
*
Mask options
and SD line have an additional mode to generate an SSI–
interrupt.
All four Port 4 pins can be individually switched by the
P4CR–register . Figure 25 shows the internal interfaces to
bidirectional Port 4.
P4DAT0
P40M2
P42M2
V DD
Bit 1
Bit 5
Bit 0
*
*
*
Pull-down
P40M1
P42M1
Bit 0
Bit 4
Pull-up
Auxiliary register address: ’4’hex
Primary register address: ’4’hex
*
*
V DD
V
DD
Reset value: 1111b
Reset value: 1111b
Reset value: 1111b
*
*
Rev. A3, 02-Apr-01
Static
Pull-up
Static
Pull-down
BPxy
13360