Content originally posted in LPCWare by ctchen on Fri Jul 24 20:45:12 MST 2015
I have a problem that UART(RS232) transmission doesn’t normal operation.
Namely, garbage value is printed on console window of PC.
The environment of my development is…
(1) MPU : LPC11C12
(2) LPCXpress 7.8
(3) J-link(segger)
I know why this problem is occurred and how this problem is solved.
Can you advise me?
* Source code
void UARTInit()
{
LPC_IOCON->PIO1_7 &= ~0x07;
LPC_IOCON->PIO1_7 |= 0x01; //UART TXD
LPC_SYSCON->SYSAHBCLKCTRL |= (1<<12);
LPC_SYSCON->UARTCLKDIV = 0x01 ;
// BAUDRATE 115200
LPC_UART->LCR = 0x83; //DLAB=1 to get access to baud dividers
//Data bit : 8bit, Stop bit : 1bit, Parity : None
LPC_UART->DLM = 0;
LPC_UART->DLL = 4;
LPC_UART->FDR = 0x85; // 12MHz, 115200: DIVADDVAL =5, MULVAL =8
LPC_UART->LCR = 0x03; // DLAB = 0
LPC_UART->FCR = 0x07; // Enable and reset TX and RX FIFO.
}
int main (void)
{
LPC_SYSCON->SYSPLLCLKSEL = 0x01 ; // 12MHz, System oscillator
LPC_SYSCON->MAINCLKSEL= 0x01 ; // 12MHz, Input clock to system PLL
Unsigned char data = ‘A’ ;
UARTInit() ;
while (1)
{
while (!(LPC_UART->LSR & 0x40)) ;
LPC_UART->THR = data ;
}
}
