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M0A21/M0A23 Series
May 06, 2022
Page
485
of 746
Rev 1.02
M0
A21
/M
0
A
2
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SE
RIES
TEC
H
NICAL
RE
FEREN
C
E
M
ANUAL
6.12 USCI - Universal Serial Control Interface Controller (USCI)
6.12.1 Overview
The Universal Serial Control Interface (USCI) is a flexible interface module covering several serial
communication protocols. The user can configure this controller as UART, SPI, or I
2
C functional
protocol.
6.12.2 Features
The controller can be individually configured to match the application needs. The following protocols are
supported:
UART
SPI
I
2
C
6.12.3 Block Diagram
Peripheral
Device
User
Interface
Control Register
Data
Buffer
Data
Shift
Unit
Protocol
Processor
Unit
(UART, SPI,
I
2
C)
Input
Processor
Buffer
Control
Interrupt
Generation
USCIx_DAT0/1
To Interrupt
Signal
USCIx_CLK
USCIx_CTL0/1
Wake-up
Control
Protocol-Relative
Clock Generator
f
PCLK
Output
Configuration
Note:
x = 0, 1
Figure 6.12-1 USCI Block Diagram
6.12.4 Functional Description
The structure of the Universal Serial Control Interface (USCI) controller is shown in Figure 6.12-1. The
input signal is implemented in input processor. The data buffers and the data shift unit support the data
transfers. Each protocol-specific function is handled by the protocol processor unit. The timing and time
event control signals of the specific protocol are handled by the protocol-relative clock generator. All the
protocol-specific events are processed in the interrupt generation unit. The wake-up function of the
specific protocol is implemented in the wake-up control unit.
The USCI is equipped with three protocols including UART, SPI, and I
2
C. They can be selected by
FUNMODE (USCI_CTL [2:0]). Note that the FUNMODE must be set to 0 before changing protocol.