Example Of Memory Connection - NEC 78014Y Series User Manual

8-bit single-chip microcontrollers

Table of Contents

19.4 Example of Memory Connection

An example of external memory connection with the µ PD78014 is shown in Figure 19-7. SRAM is used as the

external memory in this application example. In addition, the external device expansion function is used in the full-

address mode, and the internal ROM is allocated to addresses 0000H to 7FFFH (32 Kbytes), and SRAM is allocated

to addresses above 8000H.

www.DataSheet4U.com

At the external memory read modify write timing, the time from RD signal rising to write data output

is very short, so that the write data sometimes conflicts with the output data from external memory

(SRAM, etc). In this case, it is possible to avoid data conflict by not using the following instructions

which generate read modify write timing.

CHAPTER 19 EXTERNAL DEVICE EXPANSION FUNCTION

Figure 19-7. Example of Memory Connection with µ PD78014

A, [HL + byte]

[HL].bit, CY

[HL].bit, $addr16

I/O1 to I/O8