10.3.6
Alternate Functions of Port E
The Port E pins with alternate functions are shown in Table 10-15.
Table 10-15. Port E Pins Alternate Functions
Port Pin Alternate Function
INT7/AIN.1/UVCON (External Interrupt 7 Input, Analog Comparator Positive Input
or VBUS Control)
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
INT6/AIN.0 (External Interrupt 6 Input or Analog Comparator Positive Input)
INT5/TOSC2 (External Interrupt 5 Input or RTC Oscillator Timer/Counter2))
INT4/TOSC2 (External Interrupt4 Input or RTC Oscillator Timer/Counter2)
UID
ALE/HWB (Address latch to extenal memory or Hardware bootloader activation)
RD (Read strobe to external memory)
WR (Write strobe to external memory)
• INT7/AIN.1/UVCON – Port E, Bit 7
INT7, External Interrupt source 7: The PE7 pin can serve as an external interrupt source.
AIN1 – Analog Comparator Negative input. This pin is directly connected to the negative input of
the Analog Comparator.
UVCON - When using USB host mode, this pin allows to control an external VBUS generator
(active high).
• INT6/AIN.0 – Port E, Bit 6
INT6, External Interrupt source 6: The PE6 pin can serve as an external interrupt source.
AIN0 – Analog Comparator Negative input. This pin is directly connected to the negative input of
the Analog Comparator.
• INT5/TOSC2 – Port E, Bit 5
INT5, External Interrupt source 5: The PE5 pin can serve as an External Interrupt source.
TOSC2, Timer/Counter2 Oscillator pin1. When the AS2 bit in ASSR is set to enable asynchro-
nous clocking of Timer/Counter2, pin PE5 is disconnected from the port, and becomes the ouput
of the inverting Oscillator amplifier. In this mode, a crystal is connected to this pin, and the pin
can not be used as an I/O pin.
• INT4/TOSC1 – Port E, Bit 4
INT4, External Interrupt source 4: The PE4 pin can serve as an External Interrupt source.
TOSC1, Timer/Counter2 Oscillator pin2. When the AS2 bit in ASSR is set to enable asynchro-
nous clocking of Timer/Counter2, pin PE4 is disconnected from the port, and becomes the input
of the inverting Oscillator amplifier. In this mode, a crystal is connected to this pin, and the pin
can not be used as an I/O pin.
• UID – Port E, Bit 3
ID pin of the USB bus.
• ALE/HWB – Port E, Bit 2
88
AT90USB64/128
7593A–AVR–02/06
ATMEL [ ATMEL ]
