Atmel AT90S2313 - Alternate Functions of Port B

AT90S2313
48
n: 7,6…0, pin number.
Alternate Functions of Port B
The alternate pin functions of Port B are:
•
SCK - Port B, Bit 7
SCK, Clock input pin for memory up/downloading.
•
MISO - Port B, Bit 6
MISO, Data output pin for memory uploading.
•
MOSI - Port B, Bit 5
MOSI, Data input pin for memory downloading.
•
OC1 - Port B, Bit 3
OC1, Output compare match output: The PB3 pin can serve as an external output for timer 1 compare match. The PB3 pin
has to be configured as an output (DDB3 is set (one)) to serve this function. See the timer description for further details,
and how to enable the output.
•
AIN1 - Port B, Bit 1
AIN1, Analog Comparator Negative Input. When configured as an input (DDB1 is cleared (zero)) and with the internal MOS
pull up resistor switched off (PB1 is cleared (zero)), this pin also serves as the negative input of the on-chip analog
comparator.
•
AIN0 - Port B, Bit 0
AIN0, Analog Comparator Positive Input. When configured as an input (DDB0 is cleared (zero)) and with the internal MOS
pull up resistor switched off (PB0 is cleared (zero)), this pin also serves as the positive input of the on-chip analog
comparator.
Table 18. DDBn Effects on Port B Pins
DDBn PORTBn I/O Pull up Comment
0 0 Input No Tri-state (Hi-Z)
0 1 Input Yes PBn will source current if ext. pulled low.
1 0 Output No Push-Pull Zero Output
1 1 Output No Push-Pull One Output