Datasheet

79
7593L–AVR–09/12
AT90USB64/128
Note: 1. ADA is short for ADdress Active and represents the time when address is output. See “Exter-
nal memory interface” on page 31 for details.
11.3.3 Alternate functions of Port B
The Port B pins with alternate functions are shown in Table 11-6.
The alternate pin configuration is as follows:
• OC0A/OC1C/PCINT7, bit 7
OC0A, Output Compare Match A output: The PB7 pin can serve as an external output for the
Timer/Counter0 Output Compare. The pin has to be configured as an output (DDB7 set “one”) to
serve this function. The OC0A pin is also the output pin for the PWM mode timer function.
Table 11-5. Overriding signals for alternate functions in PA3..PA0.
Signal
name PA3/AD3 PA2/AD2 PA1/AD1 PA0/AD0
PUOE SRE SRE SRE SRE
PUOV
~(WR | ADA) •
PORTA3 • PUD
~(WR | ADA) •
PORTA2 • PUD
~(WR | ADA) •
PORTA1 • PUD
~(WR | ADA) •
PORTA0 • PUD
DDOE SRE SRE SRE SRE
DDOV WR
| ADA WR | ADA WR | ADA WR | ADA
PVOE SRE SRE SRE SRE
PVOV
A3 • ADA | D3
OUTPUT • WR
A2• ADA | D2
OUTPUT • WR
A1 • ADA | D1
OUTPUT • WR
A0 • ADA | D0
OUTPUT • WR
DIEOE 0 0 0 0
DIEOV 0 0 0 0
DI D3 INPUT D2 INPUT D1 INPUT D0 INPUT
AIO – – – –
Table 11-6. Port B pins alternate functions.
Port pin Alternate functions
PB7
OC0A/OC1C/PCINT7 (Output Compare and PWM Output A for Timer/Counter0,
Output Compare and PWM Output C for Timer/Counter1 or Pin Change Interrupt 7)
PB6
OC1B/PCINT6 (Output Compare and PWM Output B for Timer/Counter1 or Pin
Change Interrupt 6)
PB5
OC1A/PCINT5 (Output Compare and PWM Output A for Timer/Counter1 or Pin
Change Interrupt 5)
PB4
OC2A/PCINT4 (Output Compare and PWM Output A for Timer/Counter2 or Pin
Change Interrupt 4)
PB3
PDO/MISO/PCINT3 (Programming Data Output or SPI Bus Master Input/Slave
Output or Pin Change Interrupt 3)
PB2
PDI/MOSI/PCINT2 (Programming Data Input orSPI Bus Master Output/Slave Input
or Pin Change Interrupt 2)
PB1 SCK/PCINT1 (SPI Bus Serial Clock or Pin Change Interrupt 1)
PB0 SS
/PCINT0 (SPI Slave Select input or Pin Change Interrupt 0)