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CONNECTION WITH EXTERNAL DEVICES
12.1 Signals required for accessing external devices
This chapter describes functions to connect devices externally.
12.1 Signals required for accessing external devices
The functions and operation of the signals which are required for accessing external devices are described
below.
When connecting an external device that requires a long access time, refer to sections "12.2 Bus cycle,"
"12.3 Ready function," and "12.4 Hold function," as well as this section.
12.1.1 Descriptions of signals
When an external device is connected, operate the microcomputer in the memory expansion or microprocessor
mode. (Refer to section "2.5 Processor modes.") In these modes, pins P0 to P4 and the E pin function
as I/O pins for the signals required for accessing external devices.
Figure 12.1.1 shows the pin configuration in the memory expansion and microprocessor modes. Table
12.1.1 lists the functions of pins P0 to P4 and the E pin in the memory expansion and the microprocessor
modes.
12–2
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7751 Group User's Manual
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