
R01UH0336EJ0102 Rev.1.02
Page 197 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 5 DMA Module
5.3 Overview
Direct memory access (DMA) is used to access data without going through the
CPU.
Internally, the subsystem of this product consists of two units: the DMAC and
DTFR (DMA trigger factor register).
The DMAC is capable of transferring data at high speeds using the internal
system bus.
The DTFR has the function of selecting DMA transfer sources from interrupt
requests.
5.3.1
Functions of the DMA Controller (DMAC)
• The DMAC includes registers for storing transfer information (transfer
address, transfer unit size, etc.) and for control.
• When a DMA transfer request is accepted, a transfer request is output to the
DMAT, according to the transfer information it contains.
• Hardware DMA transfer requests, DMA acknowledge signals, and DMA
transfer completion interrupts are input and output.
• Write-back information is written back to the registers.
5.3.2
Function of the DMA Trigger Factor Register (DTFR)
• This register selects DMA transfer sources from among the interrupt signals
(triggers for the 8 channels are selected from among the m =108 interrupt
signals).
Note
For the addresses of the target areas for transfer, refer to Figure 5-2, Memory
Map as Seen from the DMA.
Table 5-3
Target Spaces for DMA Transfer
Destination
Source
Peripheral I/O
(PBUS)
On-chip RAM
On-Chip Code
Flash
On-Chip Data
Flash
Peripheral I/O (PBUS)
OK
OK
NG
NG
On-chip RAM
OK
OK
NG
NG
On-chip code flash
OK
OK
NG
NG
On-chip data flash
OK
OK
NG
NG
Содержание V850 Series
Страница 1556: ...V850E2 PG4 L R01UH0336EJ0102 Back Cover ...