AT90CAN32_14 Datasheet, PDF (88/428 Pages) ATMEL Corporation – High-performance, Low-power AVR 8-bit Microcontroller

9.3.8
Alternate Functions of Port G
The alternate pin configuration is as follows:
Table 9-21.
Port Pin
PG4
PG3
PG2
PG1
PG0
Port G Pins Alternate Functions
Alternate Function
TOSC1 (RTC Oscillator Timer/Counter2)
TOSC2 (RTC Oscillator Timer/Counter2)
ALE (Address Latch Enable to external memory)
RD (Read strobe to external memory)
WR (Write strobe to external memory)
The alternate pin configuration is as follows:
• TOSC1 – Port G, Bit 4
TOSC2, Timer/Counter2 Oscillator pin 1. When the AS2 bit in ASSR is set (one) to enable asyn-
chronous clocking of Timer/Counter2, pin PG4 is disconnected from the port, and becomes the
input of the inverting Oscillator amplifier. In this mode, a Crystal Oscillator is connected to this
pin, and the pin can not be used as an I/O pin.
• TOSC2 – Port G, Bit 3
TOSC2, Timer/Counter2 Oscillator pin 2. When the AS2 bit in ASSR is set (one) to enable asyn-
chronous clocking of Timer/Counter2, pin PG3 is disconnected from the port, and becomes the
inverting output of the Oscillator amplifier. In this mode, a Crystal Oscillator is connected to this
pin, and the pin can not be used as an I/O pin.
• ALE – Port G, Bit 2
ALE is the external data memory Address Latch Enable signal.
• RD – Port G, Bit 1
RD is the external data memory read control strobe.
• WR – Port G, Bit 0
WR is the external data memory write control strobe.
88 AT90CAN32/64/128
7679H–CAN–08/08