HD64F2149 Datasheet, PDF (222/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

7.4 Interrupts
An interrupt request is issued to the CPU when the DTC finishes the specified number of data
transfers, or a data transfer for which the DISEL bit was set to 1. In the case of interrupt activation,
the interrupt set as the activation source is generated. These interrupts to the CPU are subject to
CPU mask level and interrupt controller priority level control.
In the case of activation by software, a software-activated data transfer end interrupt (SWDTEND)
is generated.
When the DISEL bit is 1 and one data transfer has ended, or the specified number of transfers
have ended, after data transfer ends, the SWDTE bit is held at 1 and an SWDTEND interrupt is
generated. The interrupt handling routine should clear the SWDTE bit to 0.
When the DTC is activated by software, an SWDTEND interrupt is not generated during a data
transfer wait or during data transfer even if the SWDTE bit is set to 1.
7.5 Usage Notes
Module Stop: When the MSTP14 bit in MSTPCR is set to 1, the DTC clock stops, and the DTC
enters the module stop state. However, 1 cannot be written in the MSTP14 bit while the DTC is
operating. When the DTC is placed in the module stop state, the DTCER registers must all be in
the cleared state when the MSTP14 bit is set to 1.
On-Chip RAM: The MRA, MRB, SAR, DAR, CRA, and CRB registers are all located in on-chip
RAM. When the DTC is used, the RAME bit in SYSCR must not be cleared to 0.
DTCE Bit Setting: For DTCE bit setting, read/write operations must be performed using bit-
manipulation instructions such as BSET and BCLR. For the initial setting only, however, when
multiple activation sources are set at one time, it is possible to disable interrupts and write after
executing a dummy read on the relevant register.
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