Maxim Integrated MAXQ Family Users Guide: MAXQ8913 Supplement - Manual (Page 44)

MAXQ Family User’s Guide:
MAXQ8913 Supplement
10-1
ADDENDUM TO SECTION 10: SERIAL I/O MODULE
The MAXQ8913 provides one serial universal synchronous/asynchronous receiver-transmitter (USART) interface that
operates as described in the MAXQ Family User’s Guide.
10.1 Serial USART I/O Pins and Control Registers
Table 10-1. Serial USART Input and Output Pins
Table 10-2. Serial USART Control Registers
10.2 Serial USART Code Examples
10.2.1 Serial USART Example: Echo Characters in 10-Bit Asynchronous Mode
move SCON.6, #1 ; Set to mode 1 (10-bit asynchronous)
move SCON.4, #1 ; Enable receiver
move SMD.1, #1 ; Baud rate = 16 x baud clock
move PR, #007DDh ; P = 2^21 * 9600 / 10.000MHz
move SCON.0, #0 ; Clear received character flag
move SCON.1, #0 ; Clear transmit character flag
move Acc, #0Dh
call TxChar
move Acc, #0Ah
call TxChar
move Acc, #’>’
call TxChar
move Acc, #’ ‘
call TxChar
mainLoop:
call RxChar
call TxChar
jump mainLoop
SERIAL USART FUNCTION PIN MULTIPLEXED WITH GPIO
RX: Serial Receive M3 P1.1
TX: Serial Transmit N4 P1.0
REGISTER ADDRESS FUNCTION
SCON M1[00h] Serial Port Control Register. Serial port mode, receive enable, 9th bit control, and interrupt flags.
SBUF M1[01h] Serial Port Data Buffer. Input and output data buffer.
SMD M1[08h] Serial Port Mode Register. Controls baud rate, interrupt enable, and framing error detection.
PR M1[09h] Serial Port Phase Register. Contains counter reload value for baud-rate generation.
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