•
Address register (ADDR)
Optional write-protection by the Peripheral Access Controller (PAC) is denoted by the "PAC Write-
Protection" property in each individual register description.
PAC write-protection does not apply to accesses through an external debugger.
Related Links
PAC - Peripheral Access Controller
on page 50
31.5.9. Analog Connections
Not applicable.
31.6. Functional Description
31.6.1. Principle of Operation
The basic structure of the SERCOM serial engine is shown in
. Labels in capital letters are
synchronous to the system clock and accessible by the CPU; labels in lowercase letters can be
configured to run on the GCLK_SERCOMx_CORE clock or an external clock.
Figure 31-2. SERCOM Serial Engine
Transmitter
Baud Rate Generator
= =
Selectable
Internal Clk
(GCLK)
Ext Clk
Receiver
Address Match
baud rate generator
tx shift register
rx shift register
rx buffer
status
BAUD
TX DATA
ADDR/ADDRMASK
RX DATA
STATUS
1/- /2- /16
The transmitter consists of a single write buffer and a shift register.
The receiver consists of a two-level receive buffer and a shift register.
The baud-rate generator is capable of running on the GCLK_SERCOMx_CORE clock or an external
clock.
Address matching logic is included for SPI and I
2
C operation.
31.6.2. Basic Operation
31.6.2.1. Initialization
The SERCOM must be configured to the desired mode by writing the Operating Mode bits in the Control
A register (CTRLA.MODE). Refer to table SERCOM Modes for details.
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
595