PMA51XX Datasheet, PDF (32/202 Pages) Infineon Technologies AG – RF Transmitter ASK/FSK 315/434/868/915 MHz, Embedded 8051 Microcontroller, 10-bit ADC

2.1.2 State Description
PMA51xx
Functional Description
2.1.2.1 INIT state
This is a transient state after the System Reset, which is entered when the settings of PP0, PP1, MSE, TSE, and
the Lockbyte 2 lead to NORMAL mode (please refer to Table 4 “Operating Mode Selection after Reset” on
Page 30). It is also a transient state in NORMAL mode before the state change between PDWN and RUN or when
a watchdog reset occurs in IDLE or RUN state. In INIT state, the relevant SFRs get reset to their default values.
Then the application program in FLASH is started at 4000_H and the device enters RUN state.
2.1.2.2 RUN state
In the RUN state, the CPU executes the FLASH code. Peripherals are on or off according to the application
program and the Watchdog Timer is active. All wake-up events except in ExtWUFs are ignored in the RUN state
but the corresponding wake-up flags get set and can be read and cleared. Activity on the external wake-up pins
can be monitored in the corresponding SFR P1In or P3In.
2.1.2.3 IDLE state
In the IDLE state, the CPU clock is disabled but peripherals (Timers, ADC, RF-TX, LF-RX, SPI and I²C interface)
continue normal operation. If a resume event occurs, the RUN state is reentered immediately. The Watchdog
Timer is active and reset automatically when entering IDLE state. All wake-up events are ignored in IDLE state,
but the corresponding flags are set if a wake-up occurs and can be evaluated once the device returns to the RUN
state.
If a peripheral requests an interrupt or an external interrupt occurs, the IDLE state is left for RUN state, the interrupt
service routine is executed, and on the next RETI (return from interrupt) instruction the IDLE state is re-entered in
case no resume event has occurred in between.
Resume events
The resume source can be identified by reading the Resume Event Flag, REF. Resume events may occur on the
following events:
• RF Transmitter buffer empty
• RF transmission finished
• LF Receiver buffer full
• Timer 2 underflow
• A/D conversion finished
• 2 kHz RC LP oscillator calibration finished
• Clock change from 12 MHz RC HF oscillator to crystal oscillator finished
Interrupt requests
Interrupts during IDLE state may be requested by embedded peripherals or external events.
• External (pin) interrupt 0/1
• Timer 0/1/2/3
• I2C interface
• SPI interface
• LF Receiver
• Manchester/Biphase Encoder
Data Sheet
32
Revision 2.1, 2010-06-02