MSP430通用同步异步接收,传送通信接口

Contents
1 Introduction   1
1.1 Attributes of the MSP430 UART    . . . 3
1.2 Data Format   . 3
1.3 UART Hardware Registers  . 4
2 Baud Rate Generation    . . 6
2.1 Baud Rate Generation With the MCLK    8
2.2 Baud Rate Generation With the ACLK    . 9
3 Software Routines   10
3.1 Non-Interrupt Processing  . 10
3.2 Interrupt Processing   . 12
3.2.1 MCLK Used as UART Clock    . 12
3.2.2 ACLK Used as UART Clock    . 16
3.3 Subroutines and .MACROs     . . 20
3.3.1 Subroutines   . 20
3.3.2 .MACROs   . . . 21
4 References   24
Appendix A Definitions    A-1
List of Figures
1 MSP430 USART Module    . . 2
2 USART Switched to the UART Mode     . . 3
3 RS232 Format (Levels at the MSP430)     4
4 RS232 Format (Levels on the Transmission Line)    . 4
5 USART Control Registers Used in the UART Mode    . 5
6 Baud Rate Generator   . 6
7 Function of the Baud Rate Correction     . . 8
List of Tables
1 Content of Baud Rate Registers UBR (MCLK = 1.048 MHz)    . 9
2 Content of Baud Rate Registers UBR (ACLK = 32,768 Hz)    . 10