我的while循环挂在GPS的某个地方

没有错误的检查。光照一个LED或一些东西不会有什么伤害，所以你知道这正在发生。这是更有效的（你的代码等待一个空的移位寄存器，而不是空的缓冲器）。不要尝试滚动你自己的延迟。乐观者会把你绊倒的。做这个



      以下为原文

    char UART_Read(){
    while(!RCIF);                   // while reception not complete (p215)
    return RCREG;}                // 8-bit received data

There's no checking for errors.
char UART_Read(){
    while(!RCIF);                   // while reception not complete (p215)
    if (OVRN) {
        CREN=0;    // toggle CREN off and on to clear overrun
        CREN=1;
    }
    return RCREG;}                // 8-bit received data
and it wouldn't hurt to light an LED or something so you know this is happening.
 
void UART_Data(char data){
    while (!TRMT);                                       // Wait for empty transmit buffer (p204)
    TXREG = data;}                                  // EUSART Transmit Register (loading data into)

This is more efficient (your code waits for an empty shift register, not empty buffer.)
void UART_Data(char data){
    while (!TXIF);                                       // Wait for empty transmit buffer
    TXREG = data;}                                  // EUSART Transmit Register (loading data into)

 
void Delay_Ms(unsigned int delay){
    unsigned int i,j;
    for(i=0; i     for(j=0; j<1000; j++);}
Don't try to roll your own delays. The optimiser will trip you up. Make this
void Delay_Ms(unsigned int delay){
    do {
        __delay_ms(1);
    } while (--delay);
}
 

什么是OVRN？未识别，在数据表中，我看到ORR（溢出错误位），



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    What is the OVRN ? not recognized, In datasheet I do see OERR (overrun error bit),

我把它放了，修理好了！！！！你今天帮了我很大的忙：非常高兴！谢谢！



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    I put OERR, Fixed it !!!! Man you have helped me GREATLY today :) Very happy!! thankyou
 

您需要根据需要设置寄存器的顺序读取数据表以正确初始化UART。第211页第18.2.1节的列表（底部文本，右手列）清楚地显示了这一点。UART是那些具有非常明确的初始化序列的外围设备之一，如果不遵循，可能会发生奇怪的事情。我怀疑您的“DelayyMs”函数不会像您预期的那样工作，特别是当您发布版本时。编译器的任何优化都会将该函数还原为“NOP”，并且根本不提供延迟。编译器为你提供延迟宏/函数，这些都应该被使用。“xc.h”包括编译器需要看到的第一件事。对代码的快速扫描表明，你没有使用任何“STDIO”、“STDLIB”、“String”和“STNDIt”。这些通常用于非嵌入式系统，但对嵌入式代码（通常）有限或不使用。所有的标准都说，它将返回它遇到的第一个字符错误匹配，直到它看到两个字符串的结尾。如果一个字符串比另一个字符串长（因为‘缓冲区’可能比‘GPS*报头’长），那么在短字符串的末尾就不能得到匹配。使用“StrncMP”代替。无论如何，解析正在使用的NMEA字符串的方法可能相当容易出错。最好在整个字符串中读取，使用'n '作为结束标记，进入循环缓冲区，然后使用各种字符串处理函数解析字符串（Strutk等是相当强大的），如果您不想创建适当的解析器。G显示在作用域上（我想是UART输出），代码停止的地方，我猜想它正等待UART读取。但是，你需要用调试器进入这个代码，当它循环时，暂停它，看看到底发生了什么。苏珊。



      以下为原文

    You need to read the data sheet on the order in which the registers need to be set to properly initialise the UART. The list (bottom text, right hand column) of Section 18.2.1 on page 211 shows this clearly. The UART is one of those peripherals that have a very definite initialisation sequence and strange things can happen if it is not followed.
I suspect that your 'Delay_Ms' function will not work as you expect it to, especially when you do a release build. Any optimisation by the compiler will reduce that function to a 'nop' and provide no delay at all. The compiler provides delay macros/functions for you and these should be used.
The 'xc.h' include really needs to be the first thing the compiler sees.
A quick scan of your code shows that you are not using any of the 'stdio', 'stdlib', 'string' and 'stdint' includes. These are typically used for non-embedded systems but are (normally) limited or no use for embedded code.
Be careful of comparing strings of equal length with the 'strcmp' function. All the standard says is that it will return the first character mis-match it encounters before it sees the end of both strings. If one string is longer than the other (as 'buffer' probably longer than 'gps_header') then you don't get the match at the end of the shorter string. Use 'strncmp' instead.
Anyway,the approach to parsing the NMEA string you are using can be rather error-prone. It is better to read in the entire string, using the 'n' as the end marker, into a circular buffer and then parse the  entire string using the various string handling functions (strtok and the like are rather powerful) if you don't want to create a proper parser.
Without knowing exactly what is being displayed on the scope (I think it is the UART output) and where the code is stopping, I would guess that it is sitting waiting for a UART read. 
However you need to get into this code with a debugger and pause it when it loops to see what is really going on.
Susan

我的记忆力差。我应该检查一下，但是你找到了正确的一点。如果添加了代码修复了你的问题，那么你的代码就不好了。如果你得到了溢出错误，那就意味着你没有足够快地检查RCIF位，而你真的需要使用中断来接收到FIFO缓冲区。



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My bad memory. I should have checked, but you found the right bit anyway.
If adding that code fixed your problem, then your code is bad.
If you are getting overrun errors, then it means you are not checking the RCIF bit quickly enough, and you really need to use interrupts to receive into a FIFO buffer instead.
 

因此，不是使用STRCMP（缓冲器，……），而是使用STRNCMP（？）我有一个错误切换到周围。我认为NMEA字符串与初始字符计数的长度相同，“$gpxxx，7个字符以$$开头。我最初的代码是一次读取初始字符1（如果，（g，If（p，If）（g，If，g，If）…我被告知这是一个糟糕的方法，希望我能正确地理解你，因为我对这一切都很陌生。我正在努力。



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    So instead of using 'strcmp(buffer,.......' I use strncmp(  ? I got an error switching that around. I thought the nmea strings are all same length for initial character count, "$GPxxx,  7 characters beginning with $. My original code I had was reading the initial characters 1 at a time if($, if(G, if(P, if(G, if(G, if(A  ...... I was told that was a bad approach, hope I'm understanding you correctly as I am very new to all this. I'm trying.

好，我重做角色过滤$GPGGA，我现在有GPS的进给，所以我的屏幕是刷新与活时钟和LAT/Lon，成功的夜晚。谢谢大家的帮助！



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    ok I redid the character filtering $gpgga, and I now have live GPS feed, so my screen is refreshing with live clock and lat/lon, successful night. thankyou for your help everyone!