H8SSLASH2214 datasheet(224/936 Pages) RENESAS

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Section 6 Bus Controller

Rev.4.00 Sep. 18, 2008 Page 164 of 872

REJ09B0189-0400

6.9

Resets and the Bus Controller

In a power-on reset, the H8S/2214 Group, including the bus controller, enters the reset state at that

point, and an executing bus cycle is discontinued.

In a manual reset, the bus controller’s registers and internal state are maintained, and an executing

external bus cycle is completed. In this case,

WAIT input is ignored and write data is not

guaranteed.

6.10

External Module Expansion Function

6.10.1

Overview

The H8S/2214 Group has an external module expansion function to provide for the addition of

peripheral devices. Using this function to provide a combination of H8S/2214 Group and external

modules makes it possible to implement a multichip system on the user board.

Figure 6.21 shows a block diagram.

Bus access states can be changed by means of a bus controller setting.

The

EXMS signal is output to external modules for addresses H'FFFF40 to H'FFFF5F.

Priority and DTC activation can be specified for interrupts

EXIRQ7 to EXIRQ0 in the same way

as for the H8S/2214’s on-chip supporting functions.

The DTC data transfer end signal for

EXIRQ7 to EXIRQ0 interrupt input is output from

EXDTCE. Also, the inverse of the value of bit 0 in module stop control register B is output from

EXMSTP.

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