Hi, I want to access the ADC0804 which is connected as the memory mapped device at 0x0001. Initially, I want check whether, address and data bus is working fine. For the same, I wrote the code as :::::Program 1::::: #include <p89v51rx2.h>
volatile unsigned char xdata *p = (char xdata *)0x0000; sbit LED = P3^0;
void main() { int j = 0;
while(1) { p[0] = 0x55; for(j=0; j<=2500; j++); LED = 0; p[1] = 0xAA; for(j = 0; j<=2500; j++); LED = 1; } }
:::::: Program 2:::::::::::::::: #include <p89v51rx2.h> #include <absacc.h>
volatile xdata at 0x1000 unsigned char config; volatile xdata at 0x1001 unsigned char config1; sbit LED = P3^0;
void main() { int j = 0; while(1) { config = 0xAA; for(j=0; j<=2500; j++); LED = 0; config1 = 0x55; for(j = 0; j<=2500; j++); LED = 1; } }
Program 1: LED Blinks but, there is no ALE or BUS transisitions. Program 2: Compiler through error that missing ; before 0x1000. This code I have refered from one of 8051 SBC webpage.
Kindly let me know what is the wrong? Is it, I need to set something in compiler? Iam using Keil uV4.
With thanks...
Hi James,
You need either disable that internal XRAM or -better- use a different XRAM address
I have tried address of 0x8000 and 0x0301 as well.. the bus is not toggling even there is no transistion in ALE pin. I don't know where I am missing...... Is there any thing I need to configure in compiler (Keil)?