Datasheet

80
7734Q–AVR–02/12
AT90PWM81/161
9.3.4 Alternate Functions of Port E
The Port E pins with alternate functions are shown in Table 9-9.
The alternate pin configuration is as follows:
• AREF/ADC6, Bit 3
AREF: Analog reference voltage. See Table 17-3 on page 218 for the definition of this pin.
ADC6: Analog to Digital Converter, input channel 6
.
This pin can only be used as a digital output pin. It cannot be read as a digital input.
• XTAL2/ACMP1M/PSCINr – Bit 2
XTAL2: Chip clock Oscillator pin 2. Used as clock pin for crystal Oscillator or Low-frequency
crystal Oscillator. When used as a clock pin, the pin can not be used as an I/O pin.
Table 9-8. Overriding signals for alternate functions in PD3..PD0.
Signal name
PD3/ADC1/
ACMP2_OUT
PD2/ADC0/
ACMP1
PD1/PSCOUTR0/
PSCINrB
PD0/ACMP3_OUT/SS
/
CLKO
PUOE 0 0 0 SPE.MSTR
PUOV 0 0 0 PD0.PUD
DDOE ACE2EN 0 PSCen00 ACMP3D|(SPE.MSTR)
DDOV 1 0 1 AC3EN
PVOE AC2EN 0 PSCen00 AC3EN
PVOV ACMP2_OUT 0 PSCOUT00 AVCMP3_OUT
DIEOE ADC1D ADC0D 0 0
DIEOV 0 0 0 0
DI - - PSCINrB SS
AIO ADC1 ADC0/ACMP1 - -
Table 9-9. Port E pins alternate functions.
Port pin Alternate function
PE3
AREF (Analog reference voltage)
ADC6 (Analog input channel 6)
PE2
XTAL2: XTAL Output
ACMP1M (Analog Comparator 1 Negative Input)
PCSINr (PSCR Digital Input)
PE1
XTAL1: XTAL Input
PCSIN2 (PSC 2 Digital Input)
ACMP1_OUT (Analog Comparator 1 Output)
PE0
RESET
(Reset Input)
OCD (On Chip Debug I/O)
INT2 (External Interrupt 2 Input)