HD64F2149 Datasheet, PDF (200/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

7.2.2 DTC Mode Register B (MRB)
Bit
Initial value
Read/Write
7
CHNE
Unde-
fined
—
6
DISEL
Unde-
fined
—
5
—
Unde-
fined
—
4
—
Unde-
fined
—
3
—
Unde-
fined
—
2
—
Unde-
fined
—
1
—
Unde-
fined
—
0
—
Unde-
fined
—
MRB is an 8-bit register that controls the DTC operating mode.
Bit 7—DTC Chain Transfer Enable (CHNE): Specifies chain transfer. In chain transfer,
multiple data transfers can be performed consecutively in response to a single transfer request.
With data transfer for which CHNE is set to 1, there is no determination of the end of the specified
number of transfers, clearing of the interrupt source flag, or clearing of DTCER.
Bit 7
CHNE
0
1
Description
End of DTC data transfer (activation waiting state is entered)
DTC chain transfer (new register information is read, then data is transferred)
Bit 6—DTC Interrupt Select (DISEL): Specifies whether interrupt requests to the CPU are
disabled or enabled after a data transfer.
Bit 6
DISEL
0
1
Description
After a data transfer ends, the CPU interrupt is disabled unless the transfer counter is
0 (the DTC clears the interrupt source flag of the activating interrupt to 0)
After a data transfer ends, the CPU interrupt is enabled (the DTC does not clear the
interrupt source flag of the activating interrupt to 0)
Bits 5 to 0—Reserved: In the chip these bits have no effect on DTC operation, and should always
be written with 0.
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