SAM4L Datasheet, PDF (647/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
25. Picopower UART (PICOUART)
Rev: 1.0.1.0
25.1 Features
• Ultra low power UART RX line with fixed format :
– 9600 bauds
– 1 start bit
– 8-bit data
– No parity bit
– 1 stop bit
• Use very low power 32kHz or 1kHz reference clock (Internal RC or Crystal)
• Event system support and device wake-up source
– start bit detection
– full frame reception
– character recognition
• All low power modes supported included backup mode
25.2 Overview
The Picopower UART peripheral provides a minimalistic UART RX line feature in any of the low
power modes including backup mode. It allows the device to be waken up from any of low-power
modes by monitoring the RX line. It also able to generate an event to the Peripheral Event Con-
troller (PEVC).
The PICOUART is usually associated with another USART in the system, sharing the same
RXD pin. The PICOUART is then used to wake-up the device and the USART provides the full
UART RX/TX feature when the device is waken up
The number of PICOUART modules implemented is device specific. Refer to the Module Config-
uration section for details.
25.3 Block Diagram
Figure 25-1. PICOUART Block Diagram
BPM
PEVC
CLK32
W ake
Event
P e rip h e ra l
Bus
C L K _P IC O U A R T
RX_FSM
RHR
CFG
CR
P IC O U A R T
RXD
42023C–SAM–02/2013
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