AS (Address Strobe Input) – A positive going address strobe pulse serves to demultiplex the bus. The
falling edge of AS/ALE causes the address to be latched within the DS12C887. The next rising edge that
occurs on the AS bus will clear the address regardless of whether  CS is asserted. Access commands
should be sent in pairs.

看看原版英文資料吧,那些漏洞百出的中文翻譯會讓你抓狂的

下降沿鎖存地址,下一個(gè)上升沿清除地址

哪里不對？上升沿鎖存地址，然后讀該地址的字節(jié)內(nèi)容。讀完以后清除地址信息（應(yīng)該是置“高阻狀態(tài)”），解除對地址總線的占用，以便其他程序使用地址總線。