Datasheet

69
4317K–AVR–03/2013
AT90PWM2/3/2B/3B
11.3.1 MCU Control Register – MCUCR
• Bit 4 – PUD: Pull-up Disable
When this bit is written to one, the pull-ups in the I/O ports are disabled even if the DDxn and
PORTxn Registers are configured to enable the pull-ups ({DDxn, PORTxn} = 0b01). See “Con-
figuring the Pin” on page 63 for more details about this feature.
11.3.2 Alternate Functions of Port B
The Port B pins with alternate functions are shown in Table 11-3.
The alternate pin configuration is as follows:
• PSCOUT01/ADC4/SCK – Bit 7
PSCOUT01: Output 1 of PSC 0.
ADC4, Analog to Digital Converter, input channel 4
.
SCK: Master Clock output, Slave Clock input pin for SPI channel. When the SPI is enabled as a
slave, this pin is configured as an input regardless of the setting of DDB7. When the SPI is
enabled as a master, the data direction of this pin is controlled by DDB7. When the pin is forced
to be an input, the pull-up can still be controlled by the PORTB7 bit.
• ADC7/ICP1B/PSCOUT11 – Bit 6
ADC7, Analog to Digital Converter, input channel 7
.
ICP1B, Input Capture Pin: The PB6 pin can act as an Input Capture Pin for Timer/Counter1.
PSCOUT11: Output 1 of PSC 1.
Bit 7 6 5 4 3 2 1 0
SPIPS – –PUD– – IVSEL IVCE MCUCR
Read/Write R/W R R R/W R R R/W R/W
Initial Value 0 0 0 0 0 0 0 0
Table 11-3. Port B Pins Alternate Functions
Port Pin Alternate Functions
PB7
PSCOUT01 output
ADC4 (Analog Input Channel 4)
SCK (SPI Bus Serial Clock)
PB6
ADC7 (Analog Input Channel 7)
ICP1B (Timer 1 input capture alternate input)
PSCOUT11 output (see note 4)
PB5
ADC6 (Analog Input Channel 6)
INT2
PB4 AMP0+ (Analog Differential Amplifier 0 Input Channel )
PB3 AMP0- (Analog Differential Amplifier 0 Input Channel )
PB2
ADC5 (Analog Input Channel5 )
INT1
PB1
MOSI (SPI Master Out Slave In)
PSCOUT21 output
PB0
MISO (SPI Master In Slave Out)
PSCOUT20 output