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5. Read DTVECR again and check that it is set to the vector number (H'60). If it is not, this
indicates that the write failed. This is presumably because an interrupt occurred between steps
3 and 4 and led to a different software activation. To activate this transfer, go back to step 3.
6. If the write was successful, the DTC is activated and a block of 128 bytes of data is transferred.
7. After the transfer, an SWDTEND interrupt occurs. The interrupt handling routine should clear
the SWDTE bit to 0 and perform other wrap-up processing.
8.8
Usage Notes
8.8.1
Module Stop Mode Setting
DTC operation can be disabled or enabled using the module stop control register. The initial
setting is for DTC operation to be enabled. Register access is disabled by setting module stop
mode. Module stop mode cannot be set while the DTC is activated. For details, refer to section 22,
Power-Down Modes.
8.8.2
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.
8.8.3
DTCE Bit Setting
For DTCE bit setting, use bit manipulation instructions such as BSET and BCLR. If all interrupts
are disabled, multiple activation sources can be set at one time (only at the initial setting) by
writing data after executing a dummy read on the relevant register.
8.8.4
DMAC Transfer End Interrupt
When DTC transfer is activated by a DMAC transfer end interrupt, regardless of the transfer
counter and DISEL bit, the DMAC's DTE bit is not subject to DTC control, and the write data
has priority. Consequently, an interrupt request may not be sent to the CPU when the DTC
transfer counter reaches 0.
Note: Not supported by the H8S/2366.
8.8.5
Chain Transfer
When chain transfer is used, clearing of the activation source or DTCER is performed when
the last of the chain of data transfers is executed. SCI and high-speed A/D converter
interrupt/activation sources, on the other hand, are cleared when the DTC reads or writes to the
prescribed register.
Rev. 2.00, 05/03, page 297 of 820
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