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NUC126
Aug. 08, 2018
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Rev 1.03
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6.19 USCI - Universal Serial Control Interface Controller
6.19.1
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.
6.19.2
Features
The controller can be individually configured to match the application needs. The following protocols
are supported:
UART
SPI
I
2
C
6.19.3
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 or 2
Figure 6.19-1 USCI Block Diagram
6.19.4
Functional Description
The structure of the Universal Serial Control Interface (USCI) controller is shown in Figure 6.19-1 USCI
Block Diagram. 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 0 before changing protocol.