22
5131E-MCU Wireless-02/09
AT86RF230
The pin SLP_TR is a multifunctional pin. Depending on radio transceiver state the rising
edge of SLP_TR causes the following state transitions:
• TRX_OFF Æ SLEEP
• RX_ON Æ RX_ON_NOCLK
• PLL_ON Æ BUSY_TX
For further details to the functionality of pin SLP_TR refer to section 6.4.
The pin RST causes a reset of all registers (register bits CLKM_SHA_SEL and
CLKM_CTRL are shadowed, for details refer to section 9.6.4) and forces the radio
transceiver into TRX_OFF state. However, if the device is in the P_ON state it remains
in the P_ON state.
For all states, the state change commands FORCE_TRX_OFF or TRX_OFF lead to a
transition into TRX_OFF state. If the radio transceiver is in the BUSY_RX or BUSY_TX
state, the command FORCE_TRX_OFF interrupts the active receiving or transmitting
process, and forces an immediate transition. In contrast to that the TRX_OFF command
is stored until a currently ongoing frame reception or transmission has finished. After
the end of the frame, the transition to TRX_OFF is performed.
The completion of each requested state change shall always be confirmed by reading
the register 0x01 (TRX_STATUS).
7.1.2 Basic Operating Mode Description
7.1.2.1 P_ON - Power-on after VDD
When the external supply voltage (VDD) is firstly applied to the radio transceiver, the
system goes into the P_ON state. An on-chip reset is performed. The crystal oscillator
gets activated and the master clock is provided to the CLKM pin after the crystal
oscillator has stabilized. CLKM can be used as a clock source to the microcontroller.
The on-chip power-on-reset sets all registers to their default values. A dedicated reset
signal from the microcontroller at the pin RST is not necessary, but recommended for
hardware/software synchronization reasons. The reset impulse should have a minimum
length as specified in section 11.4, see parameter 11.4.12.
All digital inputs have pull-up or pull-down resistors (see Table 4-4). This is necessary
to support microcontrollers where GPIO signals are floating after reset. The input pull-
up and pull-down resistors are disabled when the radio transceiver leaves the P_ON
state.
Prior to leaving P_ON, the microcontroller must set all digital input pins (MOSI, RST ,
SCLK, SEL , SLP_TR) to their default operating values.
Once the supply voltage has stabilized and the crystal oscillator has settled (see section
11.5, parameter 11.5.5), a SPI write access to the register 0x02 (TRX_STATE) with the
command TRX_OFF or FORCE_TRX_OFF initiates a state change from P_ON to
TRX_OFF.
7.1.2.2 SLEEP – Sleep State
In SLEEP state, the entire radio transceiver is disabled. No circuitry is operating. The
AT86RF230 current consumption is reduced to leakage current only.
This state can only be entered from state TRX_OFF by setting the pin SLP_TR = H. If
CLKM is enabled, the SLEEP state is entered 35 CLKM cycles after the rising edge. At
that time CLKM is turned off. If the CLKM output is turned off (bits CLKM_CTRL = 0 in
register 0x03), the SLEEP state is entered immediately.