I have to program a real time clock from Dallas DS12C887. That rtc can be accessed the way external memory can be accessed, but only lower 8 bits (AD0-AD7). So, i tied to the RTC pins RD(P3.7) , WR (P3.6), ALE, and CS is a pin from P2 of AT89C52. Now i have a problem programming it, cause i've never programmed external parallel memory. My question is how can i set the ALE pin manualy or is it going higher automaticaly 1/6 of the osc. frequency? And, generally, if i can't setb and clr ALE, how can i 'catch' ALE to read and write the RTC? Is the only solution to move that connection to a free port pin?

Thank you.