Dear sir, i am is a student in physic department,i use uVision IDE for 8051 ver 6.20c, build a single board computer, with core is AT89S52,one Dallas RTC 12C887,and an 8255 PPI, both (RTC & PPI) connected to external ram addres (0x0000),selection which chip activated is done by connecting RTC cs pin to P2.7 micro by an inverter,beside it cs pin on PPI is direct connected to P2.7,i use PPI for driving LCD, and other stepper.i write code like this:
#include <REG52.H> /* define 8051 registers */ #include <stdio.h> /* define I/O functions */ #include <stdlib.h> #include <intrins.h> #include <string.h> #include <absacc.h> sbit chip_slct = P2^7; void initializePPI() { unsigned char xdata PPI_dt _at_ 0x0000; /* int at xdata 0x0*/ //unsigned char ppi_dat; //ppi_dat = XBYTE [0x0002];// = 57; chip_slct = 0; //activated PPI chip PPI_dat = 0x80; } . . . . ->>>>>> resulting error message C274 when compiling