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NUC126
Aug. 08, 2018
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Rev 1.03
NUC12
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6.23.3
Block Diagram
The UART clock control and block diagram are shown in Figure 6.23-1 and Figure 6.23-2 respectively.
Note:
The frequency of UARTx_CLK should not be greater than 30 times HCLK.
11
10
01
00
4~24 MHz
HXT
PLL FOUT
32.768kHz
LXT
22.1184MHz
HIRC
UARTSEL (CLK_CLKSEL1[25:24])
1/(1)
UARTDIV(CLK_CLKDIV0[11:8])
UART0CKEN (CLK_APBCLK0[16]
UART1CKEN (CLK_APBCLK0[17]
UART2CKEN (CLK_APBCLK0[18]
UART0_CLK
UART1_CLK
UART2_CLK
Note:
Before clock switching, both the pre-selected and
newly selected clock sources must be turned on and stable.
Figure 6.23-1 UART Clock Control Diagram
UART_CLK
IrDA Encode
TX Shift Register
TX_FIFO
RX_FIFO
RX Shift Register
IrDA Decode
Baud Out
Baud Out
Status & Control
Status & Control
Baud Rate
Generator
FIFO & Line
Control and Status
Register
MODEM
Control and Status
Register
Interrupt
Control
& status
UART Interrupt
APB_BUS
Auto Baud Rate
UART_nRTS
UART_TXD
UART_nCTS
UART_RXD
Figure 6.23-2 UART Block Diagram