Rainbow Electronics ATmega128RFA1 - Manual (Page 202)

202
8266A-MCU Wireless-12/09
ATmega128RFA1
TOSC2, Timer Oscillator pin 1: Setting the AS2 bit to one and the EXCLKAMR bit to
zero in ASSR, enables asynchronous clocking of Timer/Counter2 by a Crystal
Oscillator. The 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 Oscillator pin 2: Setting the AS2 bit to one and the EXCLKAMR bit to
zero in ASSR, enables asynchronous clocking of Timer/Counter2 by a Crystal
Oscillator. The 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.
• AMR – Port G, Bit 2
AMR, Automated Meter Reading Input: Setting the AS2 and the EXCLKAMR bits in
ASSR to one, enables asynchronous clocking of Timer/Counter2 by the AMR pin
• DIG1 – Port G, Bit 1
DIG1, Radio Transceiver Antenna Diversity Control Output: If the bit
ANT_EXT_SW_EN in ANT_DIV is set to one then the PG1 pin serves as a Radio
Transceiver output to control External Antenna Diversity.
• DIG3 – Port G, Bit 0
DIG3, Radio Transceiver RX/TX Indicator Output: If the bit PA_EXT_EN in
TRX_CTRL_1 is set to one then the PG0 pin serves as the Radio Transceiver
receive/transmit indicator output to control an external RF front-end.
Table 14-16 below relates the alternate functions of Port G to the overriding signals
shown in Figure 14-5 on page 191 .
Table 14-16. Overriding Signals for Alternate Functions PG5:PG2
Signal
Name PG5/OC0B PG4/TOSC1 PG3/TOSC2 PG2/AMR
PUOE – AS2 &
(~EXCLKAMR) AS2 &
(~EXCLKAMR) &
(~EXCLK) AS2 & EXCLKAMR
PUOV – 0 0 0
DDOE – AS2 &
(~EXCLKAMR) AS2 &
(~EXCLKAMR) &
(~EXCLK) AS2 & EXCLKAMR
DDOV – 0 0 0
PVOE OC0B Enable 0 0 0
PVOV OC0B 0 0 0
DIEOE – AS2 &
(~EXCLKAMR) AS2 &
(~EXCLKAMR) &
(~EXCLK) AS2 & EXCLKAMR
DIEOV – EXCLK 0 1
DI – – – AMR
AIO – T/C2
OSC INPUT T/C2
OSC OUTPUT –