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I write a program for serial communication over arduino due Rx1 and TX1 Ports in atmel studio 7 asf project .
when i send a char serial monitor does not show anything but when i select hex mode it show 0x00.
my serial terminal baud rate 115200. Here is my code
#include "asf.h"
Byte GetChar();void PutChar(const uint8_t c);
int main(){ SystemInit(); WDT->WDT_MR |= WDT_MR_WDDIS; /*Enable clock for USART*/ PMC->PMC_PCER0 = 1 << ID_USART0; /*Enable clock for peripheral*/ REG_PMC_PCER0 = PMC_PCER0_PID11; REG_PMC_PCER0 = PMC_PCER0_PID10; /*Disable Rx Tx PIO line*/ PIOA->PIO_PDR |= PIO_PA10A_RXD0; PIOA->PIO_PDR |= PIO_PA11A_TXD0; /*Set pins to use peripheral A*/ PIOA->PIO_ABSR &= ~PIO_PA10A_RXD0; PIOA->PIO_ABSR &= ~PIO_PA11A_TXD0; //Enable the pull up on the Rx and Tx pins PIOA->PIO_PUER |= PIO_PA10A_RXD0; PIOA->PIO_PUER |= PIO_PA11A_TXD0; /*Disable PDC Requests*/ USART0->US_PTCR = US_PTCR_RXTDIS | US_PTCR_TXTDIS;
/*Reset receiver ,transmitter & Status register, Disable RX and TX*/ USART0->US_CR= US_CR_RSTRX | US_CR_RSTTX | US_CR_RXDIS | US_CR_TXDIS |US_CR_RSTSTA; /*Disable all Interrupt*/ USART0->US_IDR = 0xFFFFFFFF; /*Select USART Normal Mode No Parity and Clock Source Internal MCU*/ USART0->US_MR = US_MR_USART_MODE_NORMAL | US_MR_USCLKS_MCK| US_MR_CHMODE_NORMAL | US_MR_CHRL_8_BIT| US_MR_PAR_NO;
/*Set the baud rate to 115200 value*/ //uint32_t baude = 115200; USART0->US_BRGR = (84000000/16*115200); /*Enable Rx and Tx communication port*/ USART0->US_CR &= ~(US_CR_RSTRX | US_CR_RSTTX | US_CR_RXDIS | US_CR_TXDIS | US_CR_RSTSTA);
/*Enable receiver and transmitter*/ USART0->US_CR= US_CR_RXEN | US_CR_TXEN; while(1) { PutChar('N'); }}
Byte GetChar(){ //Wait until receiver ready while((USART0->US_CSR & US_CSR_RXRDY)==US_CSR_RXRDY) return USART0->US_RHR;}
void PutChar(const uint8_t c){ // Check if the transmitter is ready while(!(USART0->US_CSR & US_CSR_TXRDY)); // Send the character USART0->US_THR = c;}
OK . thank you for interest on my question. The answer is as simple as quite. Baud rate calculation formula is
US_BRGR=MCK/Buad*16 ok.here MCK is 84MHz and baud is baud rate which you want.
The US_BRGR value do not except float value for example baud=115200 and MCK=84MHz the calculation US_BRGR=84MHz/(115200*16)=45.57
which is not valid. It except integer value like 45 or 46 some thing like that.
so, if we choose baud=300 and MCK=84MHz The US_BRGR=84MHz/(300*16)=17500
Here is my correct code :
int main(){SystemInit();WDT->WDT_MR |= WDT_MR_WDDIS;/*Enable clock for USART*/PMC->PMC_PCER0 = 1 << ID_USART0;/*Enable clock for peripheral*/REG_PMC_PCER0 = PMC_PCER0_PID11;REG_PMC_PCER0 = PMC_PCER0_PID10;/*Disable Rx Tx PIO line*/PIOA->PIO_PDR |= PIO_PA10A_RXD0;PIOA->PIO_PDR |= PIO_PA11A_TXD0;/*Set pins to use peripheral A*/PIOA->PIO_ABSR &= ~PIO_PA10A_RXD0;PIOA->PIO_ABSR &= ~PIO_PA11A_TXD0;//Enable the pull up on the Rx and Tx pinsPIOA->PIO_PUER |= PIO_PA10A_RXD0;PIOA->PIO_PUER |= PIO_PA11A_TXD0;/*Disable PDC Requests*/USART0->US_PTCR = US_PTCR_RXTDIS | US_PTCR_TXTDIS;
/*Reset receiver ,transmitter & Status register, Disable RX and TX*/USART0->US_CR= US_CR_RSTRX | US_CR_RSTTX | US_CR_RXDIS | US_CR_TXDIS |US_CR_RSTSTA;/*Disable all Interrupt*/USART0->US_IDR = 0xFFFFFFFF;/*Select USART Normal Mode No Parity and Clock Source Internal MCU*/USART0->US_MR = US_MR_USART_MODE_NORMAL | US_MR_USCLKS_MCK| US_MR_CHMODE_NORMAL | US_MR_CHRL_8_BIT| US_MR_PAR_NO;
/*Set the baud rate to 300 value*///uint32_t baude = 300;USART0->US_BRGR = (84000000/300*16);/*Enable Rx and Tx communication port*/USART0->US_CR &= ~(US_CR_RSTRX | US_CR_RSTTX | US_CR_RXDIS | US_CR_TXDIS | US_CR_RSTSTA);
/*Enable receiver and transmitter*/USART0->US_CR= US_CR_RXEN | US_CR_TXEN;while(1){PutChar('N');}}
Byte GetChar(){//Wait until receiver readywhile((USART0->US_CSR & US_CSR_RXRDY)==US_CSR_RXRDY)return USART0->US_RHR;}
void PutChar(const uint8_t c){// Check if the transmitter is readywhile(!(USART0->US_CSR & US_CSR_TXRDY));// Send the characterUSART0->US_THR = c;
OK. try it and send me your feedback.