EM342-RTR datasheet(23/143 Pages) SILABS

23 / 143 page

EM342

Rev 1.0

set. The processor can be operated at 12 or 24 MHz when using the high-frequency crystal oscillator, or at 6 MHz

or 12 MHz when using the high-frequency internal RC oscillator.

The EM342 has 128 kB of flash memory. The chip has 12 kB of RAM on-chip, and the ARM configurable memory

protection unit (MPU).

The EM342 implements both the ARM Serial Wire and JTAG debug interfaces. These interfaces provide real time,

non-intrusive programming and debugging capabilities. Serial Wire and JTAG provide the same functionality, but

are mutually exclusive. The Serial Wire interface uses two pins; the JTAG interface uses five. Serial Wire is

preferred, since it uses fewer pins.

The EM342 contains 16 GPIO pins shared with other peripheral or alternate functions. The integrated serial

controller SC1 can be configured for SPI (slave) or UART operation.

The EM342 contains four oscillators: a high-frequency 24 MHz external crystal oscillator, a high-frequency 12 MHz

internal RC oscillator, an optional low-frequency 32.768 kHz external crystal oscillator, and a low-frequency 10 kHz

internal RC oscillator.

The EM342 has an ultra low power, deep sleep state with a choice of clocking modes. The sleep timer can be

clocked with either the external 32.768 kHz crystal oscillator or with a 1 kHz clock derived from the internal 10 kHz

RC oscillator. Alternatively, all clocks can be disabled for the lowest power mode. In the lowest power mode, only

external events on GPIO pins will wake up the chip. The EM342 has a fast startup time (typically 110 µs) from deep

sleep to the execution of the first ARM® CortexTM-M3 instruction.

The EM342 contains three power domains. The always-on high voltage supply powers the GPIO pads and critical

chip functions. Regulated low voltage supplies power the rest of the chip. The low voltage supplies are disabled

during deep sleep to reduce power consumption. Integrated voltage regulators generate regulated 1.25 V and

1.8 V voltages from an unregulated supply voltage. The 1.8 V regulator output is decoupled and routed externally

to supply analog blocks, RAM, and flash memories. The 1.25 V regulator output is decoupled externally and

supplies the core logic.

EM342-RTR Datasheet(PDF) 23 Page - Silicon Laboratories