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8111C–MCU Wireless–09/09
AT86RF231
6.5
Sleep/Wake-up and Transmit Signal (SLP_TR)
Pin 11 (SLP_TR) is a multi-functional pin. Its function relates to the current state of the
In states PLL_ON and TX_ARET_ON, pin SLP_TR is used as trigger input to initiate a TX trans-
action. Here pin SLP_TR is sensitive on rising edge only.
After initiating a state change by a rising edge at pin SLP_TR in radio transceiver states
TRX_OFF, RX_ON or RX_AACK_ON, the radio transceiver remains in the new state as long as
the pin is logical high and returns to the preceding state with the falling edge.
SLEEP state
The SLEEP state is used when radio transceiver functionality is not required, and thus the
AT86RF231 can be powered down to reduce the overall power consumption.
TRX_OFF state the microcontroller forces the AT86RF231 to SLEEP by setting SLP_TR = H. If
pin 17 (CLKM) provides a clock to the microcontroller this clock is switched off after 35 clock
cycles. This enables a microcontroller in a synchronous system to complete its power-down rou-
tine and prevent deadlock situations. The AT86RF231 awakes when the microcontroller
releases pin SLP_TR. This concept provides the lowest possible power consumption.
The CLKM clock frequency settings for 250 kHz and 62.5 kHz are not intended to directly clock
the microcontroller. When using these clock rates, CLKM is turned off immediately when enter-
ing SLEEP state.
Table 6-8.
SLP_TR Multi-functional Pin
Transceiver Status
Function
Transition
Description
PLL_ON
TX start
Starts frame transmission
TX_ARET_ON
TX start
Starts TX_ARET transaction
TRX_OFF
Sleep
Takes the radio transceiver into SLEEP state, CLKM disabled
SLEEP
Wakeup
Takes the radio transceiver back into TRX_OFF state, level sensitive
RX_ON
Disable CLKM
Takes the radio transceiver into RX_ON_NOCLK state and disables CLKM
RX_ON_NOCLK
Enable CLKM
Takes the radio transceiver into RX_ON state and enables CLKM
RX_AACK_ON
Disable CLKM
Takes the radio transceiver into RX_AACK_ON_NOCLK state and disables
CLKM
RX_AACK_ON_NOCLK
Enable CLKM
Takes the radio transceiver into RX_AACK_ON state and enables CLKM
LH
LH
LH
HL
LH
HL
LH
HL