Simple_Z80_interface

Published:2009/7/25 5:08:00 Author:Jessie | From:SeekIC

Figure 9-22 shows the ADC0816/17 connected to form a simple interface with classic Z80-type microprocessors. The 280, even though architecturally similar to the INS8080, uses slightly different control lines to perform I/O reads and writes. NOR gates are used to strobe the I/O functions. However, the Z80 has RD (read) and WR (write) strobes, which are gated with IOREQ (I/O request). START is connected to OE. This causes a new conversion to be started whenever the data bits are read. (Such a configuration can be useful if the converter is to be continually restarted upon completion of the previous conversion.) Address bit A6 is used to drive a strobe that placed EOC on the data bus to be read by the CPU. NATIONAL SEM[CONDUCTOR, APPLICATION NOTE 258, 1994, P. 607.



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