An EPP Data Read cycle is shown in Figure 5. The host de-asserts WRITE*, places the AD8-1 lines in a high impedance state, and asserts the DSTROBE* signal. The peripheral then drives the data byte on the AD8-1 lines and re-asserts WAIT* to indicate that the data byte is valid. The host will read the data lines when it sees the WAIT* unasserted, and then de-asserts DSTROBE*. The peripheral then places the AD8-1 lines in an high impedance state and asserts WAIT* to indicate it is ready for the next cycle.
我翻译的: 主机将WRITE*信号置高,将数据线AD8-1置高阻态,把信号线DSTROBE*拉低。然后,外设将数据写入AD8-1,把WAIT*信号拉低表示数据可读。
当检测到WAIT*信号为低时,主机将读取数据。然后将DSTROBE*信号拉高。外设然后将数据线AD8-1置为高阻态,再拉低WAIT*信号线,以示可以开始下一个周期。
我对其中红色标记的单词拿不准,希望大家指点一下,谢谢! |