M44C090-H Datasheet, PDF (22/63 Pages) ATMEL Corporation – Low-Current Microcontroller for Wireless Communication

M44C090-H
M44C890-H
3.2.2 Bidirectional Port 5
This, and all other bidirectional ports include a bitwise
programmable Control Register (P5CR), which allows
the individual programming of each port bit as input or
output. It also opens up the possibility of reading the pin
condition when in output mode. This is a useful feature
for self testing and for serial bus applications.
The port pins can also be used as external interrupt inputs
(see figures 24 & 25). The interrupts (INT1 and INT6) can
be masked or independently configured to trigger on ei-
ther edge. The interrupt configuration and port direction
is controlled by the Port 5 Control Register (P5CR). An
additional low resistance pull–up/–down transistor mask
option provides an internal bus pull–up for serial bus ap-
plications.
The Port 5 Data Register (P5DAT) is I/O mapped to the
primary address register of address ’5’h and the Port 5
Control Register (P5CR) to the corresponding auxiliary
register. The P5CR is a byte-wide register and is config-
ured by writing first the low nibble then the high nibble
(see section 2.1 ”Addressing peripherals”).
I/O Bus
I/O Bus
(Data out)
DQ
P5DATy
S
Master reset
IN enable
VDD
*
Switched
Pull-up
*
V _DD
Static
Pull-up
*
BP5y
*
V _DD
*
*
Static
Pull-down
* Mask options
Switched
Pull-down
Figure 23. Bidirectional Port 5
BP52
Data in
Bidir. Port
IN_Enable
I/O–bus
INT1
INT6
I/O–bus
Data in
Bidir. Port
IN_Enable
BP51
BP53
Data in
Bidir. Port
IN_Enable
Decoder
Decoder
Decoder
Decoder
P5CR: P53M2 P53M1 P52M2 P52M1 P51M2 P51M1 P50M2 P50M1
Figure 24. Port 5 external interrupts
Data in
Bidir. Port
IN_Enable
BP50
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Rev.A3, 14-Dec-01