我已经解决这个问题很长一段时间了，并成功地获得了部分分数。我想知道我拥有的代码有什么问题，这阻止我在某些条件下成功
我需要一个 arduino 通过发送一串字符与另一个 arduino 进行通信。到目前为止，我已经成功发送和接收了一些数据，但我认为我在uart_receive_string()函数中设置的缓冲区可能存在问题。我将提供测试所需的所有必要信息和代码，如果需要更多信息，请告诉我，我很乐意提供。
这是 tinkercad 驱动程序的链接：https ://www.tinkercad.com/things/eUZqkaIHp6J
只需单击“复制和修补”并点击顶部的代码按钮即可将以下代码粘贴到其中。您需要通过下拉框选择将代码粘贴到两个 ardunios 中。
这是我正在研究的问题的标准：
这是我应该在提供的测试驱动程序中收到的输出：
这是我已经实现的当前代码：
这是两个arduino都需要复制到tinkercad中的东西
#include <stdint.h>
#include <stdio.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
void uart_putbyte(unsigned char data);
int uart_getbyte(unsigned char *buffer);
/*
** Define a function named uart_send_string which transmits the contents of
** a standard C string (i.e. a null-terminated char array) over UART. The
** function should iterate over the characters in the array, using a cast to
** convert each to an unsigned char, and transmitting the resulting byte via
** uart_putbyte. The end of the string should be signalled by sending a single
** null byte. That is, the number 0, not the character '0'.
**
** Param: str - string to be transmitted.
**
** Returns: Nothing.
*/
// vvvvvvv I need help with this vvvvvvv
void uart_send_string(char str[])
{
int i = 0;
char ch;
do{
ch = str[i];
uart_putbyte(ch);
i++;
}while(ch != '\0');
}
/*
** Define a function named uart_receive_string which uses uart_getbyte to fetch
** the contents of a standard C string (i.e. a null-terminated char array)
** from UART. The function should wait for characters, and must not return
** until a complete string has been retrieved.
**
** Note that uart_getbyte will return 1 if a byte is available, and zero
** otherwise. Therefore, to fetch a byte and store it in a variable named x,
** you will need to use a construct of the form:
** unsigned char x;
** while (! uart_getbyte(&x)) {
** // Do nothing.
** }
**
** Param: buffer - a char array which has capacity to store a string
** containing at most (buff_len-1) characters. If more than (buff_len-1)
** characters are received, the first (buff_len-1) of them should be
** stored consecutively in the buffer, and any others discarded. The
** string must be terminated correctly with a null terminator in all
** circumstances.
**
** Param: buff_len - an int which specifies the capacity of the buffer.
**
** Returns: Nothing. However, up to buff_len elements of buffer may have been
** overwritten by incoming data.
*/
//vvvvvvv I need help with this vvvvvvv
void uart_receive_string(char buffer[], int buff_len)
{
int i = 0;
unsigned char ch;
while(!uart_getbyte(&ch))
{
if(ch == 0)
{
break;
}
if(i < buff_len-1)
{
ch = buffer[i];
uart_putbyte(ch);
i++;
}
}
buffer[i]=0;
}
/*
***************************************************************************
** Initialise UART.
***************************************************************************
*/
void uart_init(void) {
UBRR0 = F_CPU / 16 / 9600 - 1;
UCSR0A = 0;
UCSR0B = (1 << RXEN0) | (1 << TXEN0);
UCSR0C = (3 << UCSZ00);
}
/*
**************************************************************************
** Send one byte, protecting against overrun in the transmit buffer.
**
** Param: data - a byte to be transmitted.
**
** Returns: Nothing.
***************************************************************************
*/
#ifndef __AMS__
void uart_putbyte(unsigned char data) {
// Wait for empty transmit buffer
while (!(UCSR0A & (1 << UDRE0)));
// Send data by assigning into UDR0
UDR0 = data;
}
#endif
/*
***************************************************************************
** Attempt to receive one byte, returning immediately to sender.
**
** Param: buffer - the address of a byte in which a result may be stored.
**
** Returns: If a byte is available returns 1 and stores the incoming byte in
** location referenced by buffer. Otherwise returns 0 and makes no other
** change to the state.
***************************************************************************
*/
#ifndef __AMS__
int uart_getbyte(unsigned char *buffer) {
// If receive buffer contains data...
if (UCSR0A & (1 << RXC0)) {
// Copy received byte from UDR0 into memory location (*buffer)
*buffer = UDR0;
//
return 1;
}
else {
return 0;
}
}
#endif
/*
***************************************************************************
** Implement main event loop.
***************************************************************************
*/
void process() {
// Use two devices, as indicated in the supplied TinkerCad model. One
// device acts as the sender (is_sender = 1), the other as receiver
// (is_sender = 0). Change this to set the role accordingly.
const int is_sender = 1;
if (is_sender) {
static char * messages_to_send[] = {
"", // Empty string
"A", // String with one symbol.
"Hello from CAB202!", // Multiple symbols
"1234567890abcdefghijklmnopqrstuvwxyz", // Longer than buffer size.
NULL, // End of list
};
static int next_message = 0;
uart_send_string(messages_to_send[next_message]);
next_message ++;
if (messages_to_send[next_message] == NULL) next_message = 0;
_delay_ms(300);
}
else {
#define BUFF_SIZE 20
char buffer[BUFF_SIZE];
uart_receive_string(buffer, BUFF_SIZE);
uart_send_string(buffer);
uart_putbyte('\r');
uart_putbyte('\n');
}
}
int main(void) {
uart_init();
while (1) {
process();
}
return 0;
}
我需要处理的这段代码的领域是：
这是发送数据所必需的：
void uart_send_string(char str[])
{
int i = 0;
char ch;
do{
ch = str[i];
uart_putbyte(ch);
i++;
}while(ch != '\0');
}
这是接收数据所必需的：
void uart_receive_string(char buffer[], int buff_len)
{
int i = 0;
unsigned char ch;
while(!uart_getbyte(&ch))
{
if(ch == 0)
{
break;
}
if(i < buff_len-1)
{
ch = buffer[i];
uart_putbyte(ch);
i++;
}
}
buffer[i]=0;
}
如果这很难理解，我真的很抱歉。我会尽力澄清所需的任何其他信息。我只需要弄清楚我做错了什么。