I have a problem running the UART, the microcontroller I am using is the SAMD21G18A and this is the code:
this is uart.h:
#ifndef _uart_H_ #define _uart_H_ /* DEFINICIONES DEL UART */ #define UART5 SERCOM5->USART extern void UART_Init(void); extern void UART_Tx(unsigned char DATO); extern unsigned char UART_Rx(void); #endif /* _uart_H_ */
this is uart.c:
#include <samd21.h> #include "uart.h" void UART_Init(void) { GCLK->GENCTRL.reg=GCLK_CLKCTRL_ID_SERCOM5_CORE|GCLK_CLKCTRL_GEN_GCLK0; //Conecta el Generador generico 0 al SERCOM5 PM->APBCMASK.reg|=PM_APBCMASK_SERCOM5; //Habilita el bus que conecta al SERCOM 5 UART5.CTRLA.reg= UART5.CTRLA.reg|=SERCOM_USART_CTRLA_DORD; //LSB se transmite primero UART5.CTRLA.reg&=~SERCOM_USART_CTRLA_CMODE; //Seleccionamos la comunicacion asincrono UART5.CTRLA.reg|=SERCOM_USART_CTRLA_FORM(0x0); //Sin paridad UART5.CTRLA.reg|=SERCOM_USART_CTRLA_TXPO(0x1)|SERCOM_USART_CTRLA_RXPO(0x3); //Configuramos el PAD[2] como Tx y el PAD[3] como Rx UART5.CTRLA.reg|=SERCOM_USART_CTRLA_SAMPR(0x3);//Selecionamos una tasa de muestreo de 8x con BAUD fracional UART5.CTRLA.reg|=SERCOM_USART_CTRLA_MODE(0x1); //Usa el reloj interno UART5.CTRLB.reg|=SERCOM_USART_CTRLB_RXEN|SERCOM_USART_CTRLB_TXEN; //Habilita los pines Rx y Tx UART5.CTRLB.reg&=~SERCOM_USART_CTRLB_SBMODE; //Con un bit de stop UART5.CTRLB.reg|=SERCOM_USART_CTRLB_CHSIZE(0x0); //Selecciona el formato de 8 bits UART5.BAUD.reg=SERCOM_USART_BAUD_FRAC_BAUD(0x68)|SERCOM_USART_BAUD_FRAC_FP(0x4); UART5.CTRLA.reg|=SERCOM_USART_CTRLA_ENABLE; //Habilita el UART 5 while(UART5.SYNCBUSY.reg&SERCOM_USART_SYNCBUSY_ENABLE); //Espera a que se habilite el UART } void UART_Tx(unsigned char DATO) { while(UART5.INTFLAG.reg&SERCOM_USART_INTFLAG_DRE); UART5.DATA.reg=DATO; } unsigned char UART_Rx(void) { while(UART5.INTFLAG.reg&SERCOM_USART_INTFLAG_RXC); return (unsigned char)UART5.DATA.reg; }
and this is the pin configuration
#ifndef _gpio_H_ #define _gpio_H_ /* DEFINICIONES DE PUERTOS */ #define PORTB PORT->Group[1] extern void GPIO_Init(void); #endif /* _gpio_H_ */
this is gpio.c
#include <samd21.h> //Device header #include "gpio.h" void GPIO_Init(void) { //Configuramos el PIN PB22 Tx PORTB.DIRSET.reg=PORT_PB22; PORTB.PINCFG[22].reg=PORT_PINCFG_PMUXEN; PORTB.PMUX[11].reg=PORT_PMUX_PMUXE(0x3); //Configuramos el PIN PB23 Rx PORTB.DIRCLR.reg=PORT_PB23; PORTB.PINCFG[23].reg=PORT_PINCFG_INEN|PORT_PINCFG_PMUXEN; PORTB.PMUX[11].reg=PORT_PMUX_PMUXO(0x3); }
The exercise that I try to do is the famous ECO, that is to say that I try that what I write in the Tx sends it again by the Rx bus, I modified it and I have tried it by the debug and it stays in the line of the uart.c
while(UART5.SYNCBUSY.reg&SERCOM_USART_SYNCBUSY_ENABLE); //Espera a que se habilite el UART
i don't know if the uart configuration is wrong or missing, i got this code from a book:"Atmel ARM Programming for Embedded Systems"authors:Muhammad Ali Mazidi,Shujen Chen,Eshragh Ghaemi.i want to know if this book is wrong and so recommended is that book or I have it wrong, thank you very much and i hope your answer soon. Before I forget, the operating frequency of the microcontroller is 8 MHz