c18 includ問題 [發表者 bmpss95102]

8-bit PIC (請註明使用元件編號):: c18 includ問題
C:\Users\USER\Desktop\PIC\myself\program_105.X\progarm_105.c:379:Error [1105] symbol 'RA0' has not been defined

我是使用pic18f4550
遇到以上問題該如何解決?
我在c18的F&Q找到了
EM-4 Compiler error: “Error [1105] symbol ‘symbol-name’ has not been
defined”
If the symbol-name is a Special Function Register (e.g., TRISB), make sure to include
the generic processor header file (#include <p18cxxx.h>) or the
processor-specific include file (e.g., #include <p18f452.h>). Special Function
Registers are declared in the processor-specific header file. Also, ensure that the
Special Function Register is in all capital letters (i.e., TRISB instead of trisb), as C
language is case-sensitive and the Special Function Registers are declared with all
capital letters.
If the symbol-name is not a Special Function Register, make sure to define the symbol
previous to its use and that the symbol name is correctly typed.

我也有 #include <p18f4550.h> 了
一樣有同樣的錯誤
該如何解決呢?