Rainbow Electronics AT86RF230 - Manual (Page 12)

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AT86RF230
5131A-ZIGB-06/14/06
The state change commands FORCE_TRX_OFF and TRX_OFF both lead to a transition into TRX_OFF state. If
the 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. On the other hand, a TRX_OFF command is
stored until a frame currently being received or transmitted is finished. After the end of the frame, the transition to
TRX_OFF is performed.
4.2. Basic Operating Mode Description
4.2.1. P_ON
When the external supply voltage (VDD) is first supplied to the transceiver IC, the system is in the P_ON (Power-
on) mode. In this mode, the crystal oscillator is activated and the master clock for the controller is provided at the
CLKM pin after a delay of 128µs to ensure a steady state of the crystal oscillator.
All digital inputs have pull-up or pull-down resistors (see Table 10-3). This is necessary to support controllers where
GPIO signals are undefined after reset. The input pull-up and pull-down resistors are disabled when the transceiver
leaves the P_ON state.
A valid SPI write access to the register TRX_STATE with the values TRX_OFF or FORCE_TRX_OFF is necessary
to leave the P_ON state.
Prior to leaving P_ON, the controller must set the pins to the default operating values: SLP_TR = 0 and 1 RST = .
An on-chip power-on-reset sets the all register to its default values. A dedicated reset signal from the controller at
the pin
RST is not necessary, but recommended for HW/SW synchronization reasons.
4.2.2. SLEEP
In SLEEP mode, the entire transceiver IC is disabled. No circuitry is running. The current consumption in this mode
is leakage current only. This mode can only be entered from state TRX_OFF, when the pin SLP_TR is set to “1”.
There is no way to switch the transceiver to SLEEP mode via SPI register access.
Leaving this state is possible in two ways:
Setting the SLP_TR pin to “0” returns the transceiver to the TRX_OFF mode without resetting any registers. Using
0 RST = resets the SPI and configuration registers to their default values and forces the IC into the TRX_OFF
mode.
4.2.3. TRX_OFF
The TRX_OFF mode provides the master clock for the controller in synchronous operation mode, allowing the
software to run without the need for the radio to be powered on. The pins SLP_TR and
RST are enabled for mode
control.
In this mode, the SPI interface and crystal oscillator are active. The voltage regulator is enabled and provides 1.8V
to the digital core for have access to the frame data buffers.
The transition from P_ON to TRX_OFF mode is described in section 4.2.1.
4.2.4. PLL_ON
Entering the PLL_ON mode from TRX_OFF will first enable the analog voltage regulator. After the voltage regulator
has settled, the PLL frequency synthesizer is enabled. When the PLL has settled at the receive frequency, a
successful PLL lock is indicated by an interrupt request at the IRQ pin.
During PLL_ON mode, the command RX_ON via register 0x02 (TRX_STATE) sets the transceiver to RX_ON
mode, even if the PLL is not yet settled.