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I am working with UART of lPC1788,in that I did the following settings for PCLK as 12MHZ and baud rate as 115200 but while I am simulating this code the baud rate is not assigned as 115200 or approx.

uint32_t uart0_init()
{

  LPC_SC->PCONP |=(1<<3);        //Enabling power/clock for UART0
  LPC_IOCON->P0_2 = 1;           //Selecting fn. 001 for P0.2(U0_TXD)
  LPC_IOCON->P0_3 = 1;           //Selecting fn. 001 for P0.3(U0_RXD)
  LPC_UART0->LCR =(0x83);        //Selecting DLAB=1,1 stop bit,Parity bit and 8-bit character length

  LPC_UART0->DLL = 0x04;         //For PCLK=12MHZ and baud rate as 115200,DLL=4(in dec.)
  LPC_UART0->DLM = 0x00;         //For PCLK=12MHZ and baud rate as 115200,DLM=0(in dec.)
  LPC_UART0->FDR =(0x85);        //DIVADDVAL=1(3:0) and MULVAL=2(7:4) in FDR calculated from the FRest value 
  LPC_UART0->LCR =(0x03);        //Disabling DLAB=0
  LPC_UART0->FCR |=(7<<0);       //Enable FIFOEN,TXFIFORES and RXFIFORES in FCR(0,1,2)

  LPC_UART0->FCR |=(0<<0);       //Disable FIFOEN,TXFIFORES and RXFIFORES in FCR(0,1,2)

  //NVIC_EnableIRQ(UART0_IRQn);

  //LPC_UART0->IER = IER_RBRIE | IER_THREIE | IER_RXIE;

  return 1;

}

For me its coming near 384615,its totally different.Is there any calculations to be done to obtain exact of 115200 baud.

Please do clear for me..

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1 回答 1

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不要使用 uart init 来更改系统控制设置。如果您不小心，您将在其他地方覆盖它们。创建 sysInit 函数并将其设置在那里。将分频器设置为 10 (0x0a)。

LPC_SC->PCLKSEL = 0x0A;

这将除以MCLK10，您将获得外设的 12Mhz 时钟。之后，您需要设置FDR和DLL设置以达到〜115200 波特。

于 2013-06-06T12:44:25.970 回答