Hi there, Given below is the program given to transfer a bit from one 68000 to another 68000 in C. Code: // PIT registers char *PACRPTR = 0x80000D; char *PADDRPTR = 0x800005; char *PBCRPTR = 0x80000F; char *PBDDRPTR = 0x800007; char *PBDRPTR = 0x800013; char *PADRPTR = 0x800011; char *PCDDRPTR = 0x800009; char *PCDRPTR = 0x800019; #define PACR (*PACRPTR) #define PADDR (*PADDRPTR) #define PADR (*PADRPTR) #define PBDDR (*PBDDRPTR) #define PBDR (*PBDRPTR) #define PBCR (*PBCRPTR) #define PCDDR (*PCDDRPTR) #define PCDR (*PCDRPTR) unsigned long int header, char temp_head[]={0x01, 0x02, 0x03, 0x04}; main() { char data_rcvd, char ack, char temp, int n=1; // configure the PIT to work with the Buffered IO Board. PACR = 0x80; PADDR = 0x0; PBCR = 0x80; PCDDR = 0x0f; PBDDR = 0xff; while(1) { temp = PCDR; //For PC4 PCDR = PCDR&0x10; ack = 0x00; //To reset ack to lo while(n<4) { while(PCDR==0x00) { PCDR = PCDR&0x10; //To keep ack at low if no strobe is received } // Read in the data from Port A data_rcvd = PADR; PBDR = PADR; PCDR = PCDR|0x01;// To make ack hi header = PBDR; temp_head[n] = header; header = header<<8; while(PCDR==0x11) //To check if strobe is hi or not { PCDR = PCDR&0x01; //To keep ack at Hi if no strobe is received } n++; } } } I need to modify the above code to share a calculation between two 68000 processors. And I need to write a probe function which will assert when calculation starts and negate when it ends. Can somebody please help me. Thanks.