SH7041A datasheet(183/923 Pages) RENESAS

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8.3.2

Activating Sources

The DTC performs write operations to the DTCSR with either interrupt sources or software as its

activating sources. Each interrupt source is designated by specific DTER bits to determine whether

it becomes an interrupt request to the CPU or a DTC activating source.

When the DISEL bit is 1, an interrupt, established as the DTC activating source, is requested of

the CPU after each data transfer in DRC. When the DISEL bit is a 0, a request is made only after

the completion of a designated number of data transfers. When the activating source interrupt is

requested of the CPU, the corresponding DTER bit is automatically cleared.

In the case of software activation also, when the DISEL bit is a 1, a software DTC activation

interrupt (SWDTCE) is requested of the CPU after each data transfer. When the DISEL bit is a 0,

a request is made only after the completion of a designated number of data transfers. When no

SWDTCE interrupt is requested of the CPU, the SWDTE bit of the DTCSR is automatically

cleared. When a request is made of the CPU, the SWDTE bit is maintained as a 1.

When multiple DTC activating sources occur simultaneously, they are accepted and the DTC is

activated in accordance with the default priority rankings shown in table 8.2.

Figure 8.3 shows a block diagram of activating source control.

IRQ

On-chip

peripheral

Interrupt

requests

Source

flag clear

Source flag clear

Interrupt requests

(those not designated as

DMAC activating sources)

CPU Interrupt requests

(those not designated as

DTC activating sources)

Clear

DTC activation request

DTC

control

DTER

DTC

INTC

DMAC

Figure 8.3 Activating Source Control Block Diagram

8.3.3

DTC Vector Table

Figure 8.4 shows the correspondence between DTC vector addresses and register information

placement. For each DTC activating source there are 2 bytes in the DTC vector table, which

contain the register information start address.

Table 8.2 shows the correspondence between activating sources and vector addresses. When

activating with software, the vector address is calculated as H'0400 + DTVEC[7:0].

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