Pin Functions in Mode 3: In mode 3 (single-chip mode), each pin can be designated for general
input or output. A pin becomes an output pin when its PBDDR bit is set to 1, and an input pin
when this bit is cleared to 0. Figure 7.21 shows the pin functions in mode 3.
Mode 3
PB7 (input/output)
PB6 (input/output)
PB5 (input/output)
PB4 (input/output)
Port B
PB3 (input/output)
PB2 (input/output)
PB1 (input/output)
PB0 (input/output)
Figure 7.21 Pin Functions in Mode 3 (Port B)
7.12.4 Input Pull-Up Transistors
Port B has built-in programmable input pull-up transistors that are available in mode 3. The pull-
up for each bit can be turned on and off individually.
An input pull-up transistor is turned on in mode 3 if 1 is written in the corresponding PBODR bit
while the corresponding PBDDR bit is cleared to 0.
The input pull-ups are turned off by a reset and in hardware standby mode. In software standby
mode, the previous state is maintained.
Table 7.24 indicates the states of the input pull-up transistors in each operating mode.
Table 7.24 States of Input Pull-Up Transistors (Port B)
Mode
Reset
Off
Hardware Standby
Software Standby
On/off
Other Operating Modes
1
2
3
Off
Off
Off
On/off
On/off
On/off
Off
On/off
Off
On/off
Notes: Off:
The input pull-up transistor is always off.
On/off: The input pull-up transistor is on if PBDR = 1 and PBDDR = 0, but off otherwise.
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HITACHI [ HITACHI SEMICONDUCTOR ]
