Procedures For Using Dtc; Activation By Interrupt; Activation By Software; Examples Of Use Of The Dtc - Hitachi H8S/2378, H8S/2378R Series Hardware Manual

9.6

Procedures for Using DTC

9.6.1

Activation by Interrupt

The procedure for using the DTC with interrupt activation is as follows:
1. Set the MRA, MRB, SAR, DAR, CRA, and CRB register information in the on-chip RAM.
2. Set the start address of the register information in the DTC vector address.
3. Set the corresponding bit in DTCER to 1.
4. Set the enable bits for the interrupt sources to be used as the activation sources to 1. The DTC
is activated when an interrupt used as an activation source is generated.
5. After the end of one data transfer, or after the specified number of data transfers have ended,
the DTCE bit is cleared to 0 and a CPU interrupt is requested. If the DTC is to continue
transferring data, set the DTCE bit to 1.
9.6.2

Activation by Software

The procedure for using the DTC with software activation is as follows:
1. Set the MRA, MRB, SAR, DAR, CRA, and CRB register information in the on-chip RAM.
2. Set the start address of the register information in the DTC vector address.
3. Check that the SWDTE bit is 0.
4. Write 1 to SWDTE bit and the vector number to DTVECR.
5. Check the vector number written to DTVECR.
6. After the end of one data transfer, if the DISEL bit is 0 and a CPU interrupt is not requested,
the SWDTE bit is cleared to 0. If the DTC is to continue transferring data, set the SWDTE bit
to 1. When the DISEL bit is 1, or after the specified number of data transfers have ended, the
SWDTE bit is held at 1 and a CPU interrupt is requested.
9.7

Examples of Use of the DTC

9.7.1

Normal Mode

An example is shown in which the DTC is used to receive 128 bytes of data via the SCI.
1. Set MRA to fixed source address (SM1 = SM0 = 0), incrementing destination address (DM1 =
1, DM0 = 0), normal mode (MD1 = MD0 = 0), and byte size (Sz = 0). The DTS bit can have
any value. Set MRB for one data transfer by one interrupt (CHNE = 0, DISEL = 0). Set the
SCI RDR address in SAR, the start address of the RAM area where the data will be received in
DAR, and 128 (H'0080) in CRA. CRB can be set to any value.
2. Set the start address of the register information at the DTC vector address.
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