EFM32WG Datasheet, PDF (504/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

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19.3.11 Pulse Generator/ Pulse Extender
The LEUART has an optional pulse generator for the transmitter output, and a pulse extender on the
receiver input. These are enabled by setting PULSEEN in LEUARTn_PULSECTRL, and with INV in
LEUARTn_CTRL set, they will change the output/input format of the LEUART from NRZ to RZI as shown
in Figure 19.7 (p. 504) .
Figure 19.7. LEUART - NRZ vs. RZI
Idle
Idle
NRZ
S
0
1
2
3
4
5
6
7
P
St op
RZ I
If PULSEEN in LEUARTn_PULSECTRL is set while INV in LEUARTn_CTRL is cleared, the output
waveform will like RZI shown in Figure 19.7 (p. 504) , only inverted.
The width of the pulses from the pulse generator can be configured using PULSEW in
LEUARTn_PULSECTRL. The generated pulse width is PULSEW + 1 cycles of the 32.768 kHz clock,
which makes pulse width from 31.25µs to 500µs possible.
Since the incoming signal is only sampled on positive clock edges, the width of the incoming pulses
must be at least two 32.768 kHz clock periods wide for reliable detection by the LEUART receiver. They
must also be shorter than half a UART baud period.
At 2400 baud/s or lower, the pulse generator is able to generate RZI pulses compatible with the IrDA
physical layer specification. The external IrDA device must generate pulses of sufficient length for
successful two-way communication.
19.3.11.1 Interrupts
The interrupts generated by the LEUART are combined into one interrupt vector. If LEUART interrupts
are enabled, an interrupt will be made if one or more of the interrupt flags in LEUARTn_IF and their
corresponding bits in LEUART_IEN are set.
19.3.12 Register access
Since this module is a Low Energy Peripheral, and runs off a clock which is asynchronous to
the HFCORECLK, special considerations must be taken when accessing registers. Please refer to
Section 5.3 (p. 21) for a description on how to perform register accesses to Low Energy Peripherals.
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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