M054ZBN Datasheet, PDF (45/68 Pages) List of Unclassifed Manufacturers – 32-BIT MICROCONTROLLER

NuMicro^™ M052/M054BN Data Sheet
6.10 UART Interface Controller (UART)
NuMicro M051^™ series provides two channels of Universal Asynchronous Receiver/Transmitters
(UART). UART0~1 performs Normal Speed UART, and support flow control function.
6.10.1 Overview
The Universal Asynchronous Receiver/Transmitter (UART) performs a serial-to-parallel
conversion on data received from the peripheral, and a parallel-to-serial conversion on data
transmitted from the CPU. The UART controller also supports IrDA SIR Function, LIN
master/slave mode function and RS-485 mode functions. Each UART channel supports seven
types of interrupts including transmitter FIFO empty interrupt (INT_THRE), receiver threshold
level reaching interrupt (INT_RDA), line status interrupt (parity error or framing error or break
interrupt) (INT_RLS), receiver buffer time out interrupt (INT_TOUT), MODEM/Wakeup status
interrupt (INT_MODEM), Buffer error interrupt (INT_BUF_ERR) and LIN receiver break field
detected interrupt (INT_LIN_RX_BREAK).
The UART0 and UART1 are built-in with a 16-byte transmitter FIFO (TX_FIFO) and a 16-byte
receiver FIFO (RX_FIFO) that reduces the number of interrupts presented to the CPU. The CPU
can read the status of the UART at any time during the operation. The reported status information
includes the type and condition of the transfer operations being performed by the UART, as well
as 3 error conditions (parity error, framing error, break interrupt) probably occur while receiving
data. The UART includes a programmable baud rate generator that is capable of dividing clock
input by divisors to produce the serial clock that transmitter and receiver need. The baud rate
equation is Baud Rate = UART_CLK / M * [BRD + 2], where M and BRD are defined in Baud Rate
Divider Register (UA_BAUD). Table 6-3 lists the equations in the various conditions and Table 6-4
list the UART baud rate setting table.
Mode DIV_X_EN DIV_X_ONE Divider X BRD M Baud rate equation
0
0
0
B
A 16 UART_CLK / [16 * (A+2)]
1
1
0
B
A B+1 UART_CLK / [(B+1) * (A+2)] , B must >= 8
2
1
1
Don‟t care A
1 UART_CLK / (A+2), A must >=3
Table 6-3 UART Baud Rate Equation
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Publication Release Date: Mar. 19, 2012
Revision V1.01