Hi all.
I am using the MT8888 together with AT89c51 on my project.
My hardware conection between the chips is that:
P1_0 D1
P1_1 D2
P1_2 D3
P1_3 D4
P1_5 ~RD
P1_6 ~WR
P1_7 IRQ/CP

i am testing it for many days and go through the data sheet for many times, and i try to follow the control logic on the data sheet.
However, i can't get any DTMF output.

My source code is as shown in the following.
Please kindly point out any problem on my source and comment on my hardare connection.
Please give some suggestion to me.




#include <AT89X51.H>
#include <intrins.h>

//function prototype

void delay(unsigned int dt);
void intial_DTMF();

void main()
{
delay(50000);
//intial_DTMF();
P1=0x60; // read the status register
_nop_ (); /* delay for hardware */
_nop_ ();
_nop_ ();

P1=0x50; //Write to control register
_nop_ (); /* delay for hardware */
_nop_ ();
_nop_ ();

P1=0x50; //Write to control register
_nop_ (); /* delay for hardware */
_nop_ ();
_nop_ ();

P1=0x58; //Write to control register
_nop_ (); /* delay for hardware */
_nop_ ();
_nop_ ();

P1=0x50; //Write to control register
_nop_ (); /* delay for hardware */
_nop_ ();
_nop_ ();


P1=0x60; //Write to control register
_nop_ (); /* delay for hardware */
_nop_ ();
_nop_ ();
//////////end intilization/////////////

P1=0x5D; // write to control regerister A
_nop_ (); /* delay for hardware */
_nop_ ();
_nop_ ();


P1=0x50; //Write to control register B
_nop_ (); /* delay for hardware */
_nop_ ();
_nop_ ();


P1=0x17; //write to transmit Data register (send a 7)
_nop_ (); /* delay for hardware */
_nop_ ();
_nop_ ();

}



//Best Regard for your help.