Hello, I am brand new to microcontrollers and I am trying to todo a small project for my electronics class. I using a AT89S52 which I program with this programmer.
As far as I can tell I have correctly programmed the device. The software for the programmer is able to program read and verify it. However when I take reset low for the chip to start running nothing happens. For simplicity of this post I have put on the following example program from the keil website (though I actually compiled it with SDCC).


/*-----------------------------------------------------------------------------
Definitions for P1.0, and P1.1.
-----------------------------------------------------------------------------*/

sbit P1_0 = 0x90^0; /* SFR for P1.0 */
sbit P1_1 = 0x90^1; /* SFR for P1.1 */

/*-----------------------------------------------------------------------------
MAIN C function
-----------------------------------------------------------------------------*/
void main (void)
{
P1_0 = 1; /* Configure P1.0 as an input */

/*-----------------------------------------------
This loop reads P1.0 and writes the value read
to P1.1.
-----------------------------------------------*/
while (1)
{
P1_1 = P1_0; /* Copy P1.0 to P1.1 */
}
}
/*---------------------------------------------------------------------------*/

Now two things....

1) If I examine the voltages on the output of all ports (P0,P1,P2,P3). I find that the P0 pins are all zero (while it says the reset value should be high = +5V). The other ports have the correct value of high = +5V.

2) Now if I take P1_0 and place it low by grounding it, I find that P1_1 does not change.

Thanks in advance for all your help,
Michael A. Balazs
Dept of Physics
University of Virginia