Hi All.

I'm using micro controller AT89C51ED2 interface with DS17887-5 in the extend board (Please see below picture)

http://www.mediafire.com/i/?98h7cnqm1g2ksx2

This is: code read/write registry of DS17887.

void WrReg(unsigned char add, unsigned char d){

EA=0;
P0 = add;
ResetWR;
ResetRD;
P0 = add;
D_CS=1;
D_ALE=1;

D_CS=0;
D_ALE=0;

P0 = d;
SetWR;
ResetWR;

D_CS=1;
D_ALE=1;
EA=1;
}

unsigned char RdReg(unsigned char add){
unsigned char d;
EA=0;
P0 = add;
ResetWR;
ResetRD;
D_CS=1;
D_ALE=1;

D_CS=0;
D_ALE=0;

SetRD;
d = P0;
ResetRD;

D_CS=1;
D_ALE=1;
EA=1;
return d;
}

void WrExt(unsigned int add, unsigned char d){
WrReg(D_EADDL, (unsigned char)(add&0x00FF)); //Set AddL
WrReg(D_EADDH, (unsigned char)((add>>8)&0x00FF)); //Set AddH
WrReg(D_EDATA, d); ////Set data
}

unsigned char RdExt(unsigned int add){
WrReg(D_EADDL, (unsigned char)(add&0x00FF)); //Set AddL
WrReg(D_EADDH, (unsigned char)((add>>8)&0x00FF)); //Set AddH

return RdReg(D_EDATA); //Read data
}




void InitRTC(){

WrReg(D_REGA, 0x30); //0011 0000 Bank1
WrReg(D_REGB, 0x02); //0000 0010 BCD, 24h
}

This is: results write/read bytes in case using 74HC245, error at bytes: 0x20, 0x40, 0x20, 0x80. With 74HCT245 then all is OK.

WR RD

Wr: 01 01
Wr: 01 01
Wr: 01 01
Wr: 01 01

Wr: 02 02
Wr: 02 02
Wr: 02 02
Wr: 02 02

Wr: 04 00
Wr: 04 00
Wr: 04 00
Wr: 04 00

Wr: 08 00
Wr: 08 00
Wr: 08 00
Wr: 08 00

Wr: 10 10
Wr: 10 10
Wr: 10 10
Wr: 10 10

Wr: 20 00
Wr: 20 00
Wr: 20 00
Wr: 20 00

Wr: 40 40
Wr: 40 40
Wr: 40 40
Wr: 40 40

Wr: 80 00
Wr: 80 00
Wr: 80 00
Wr: 80 00

If I use 74HCT245 then old board and extend board was running OK, but I replace 74HCT245 by 74HC245, then old board was still running OK, Extend Board was running error with DS17887 (Please see my test results when write/read byte 0x01, 0x02,...)

I'm using Keil C for programing.
I also try to repaire this error by changing timing read/write of software and anything by hardware, but no good results.

Please suggest me how to repaire this error.

Thanks and waiting your help.

Best Regards.