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RM0090: Reference manual - STMicroelectronics

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Universal synchronous asynchronous receiver transmitter (USART) <strong>RM0090</strong><br />

Figure 245. USART block diagram<br />

TX<br />

RX<br />

SW_RX<br />

nRTS<br />

nCTS<br />

IrDA<br />

SIR<br />

ENDEC<br />

block<br />

Hardware<br />

flow<br />

controller<br />

PWDATA<br />

CR3<br />

Transmit data register (TDR)<br />

USART<br />

interrupt<br />

control<br />

Write<br />

(CPU or DMA)<br />

Transmit Shift Register<br />

DMAT DMAR SCEN NACK HD IRLP IREN<br />

Transmit<br />

control<br />

CR2<br />

CR1<br />

TXEIE TCIE<br />

RXNE IDLE<br />

IE IE<br />

Transmitter<br />

clock<br />

/ [8 x (2 - OVER8)]<br />

SAMPLING<br />

DIVIDER<br />

USART Address<br />

f PCLKx(x=1,2)<br />

Wakeup<br />

unit<br />

RE RWU SBK<br />

Read<br />

(CPU or DMA)<br />

741/1416 Doc ID 018909 Rev 3<br />

TE<br />

CR1<br />

OVER8<br />

/USARTDIV<br />

USARTDIV = DIV_Mantissa + (DIV_Fraction / 8 × (2 – OVER8))<br />

GTPR<br />

GT<br />

TE<br />

RE<br />

(Data register) DR<br />

Receive data register (RDR)<br />

Receive Shift Register<br />

PSC<br />

CR2<br />

LINE STOP[1:0] CKEN CPOL CPHA LBCL<br />

Receiver<br />

control<br />

CR1<br />

UE M WAKE PCE PS PEIE<br />

CTS LBD<br />

Receiver<br />

clock<br />

SR<br />

TXETC RXNEIDLEORE NF FE<br />

USART_BRR<br />

Transmitter rate<br />

control<br />

DIV_Mantissa DIV_Fraction<br />

15 4<br />

0<br />

Receiver rate<br />

control<br />

Conventional baud rate generator<br />

PRDATA<br />

SCLK control SCLK<br />

PE<br />

ai16099

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