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