HD6417660 RENESAS [Renesas Technology Corp], HD6417660 Datasheet - Page 351

• Manufacturer Part Number: HD6417660
• Description: Renesas 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

10.4
When there is a DMA transfer request, the DMAC starts the transfer according to the
predetermined channel priority order; when the transfer end conditions are satisfied, it ends the
transfer. Transfers can be requested in three modes: auto request, external request, and on-chip
module request. The dual address mode has direct address transfer mode and indirect address
transfer mode. In the bus mode, the burst mode or the cycle steal mode can be selected.
10.4.1
After the DMA source address registers (SAR), DMA destination address registers (DAR), DMA
transfer count registers (DMATCR), DMA channel control registers (CHCR), DMA operation
register (DMAOR), and DMA extension resource source selector (DMARS) are set, the DMAC
transfers data according to the following procedure:
1. Checks to see if transfer is enabled (DE = 1, DME = 1, TE = 0, AE = 0, NMIF = 0)
2. When a transfer request comes and transfer is enabled, the DMAC transfers 1 transfer unit of
3. When the specified number of transfer have been completed (when DMATCR reaches 0), the
4. When an NMI interrupt is generated, the transfer is aborted. Transfers are also aborted when
data (depending on the TS0 and TS1 settings). For an auto request, the transfer begins
automatically when the DE bit and DME bit are set to 1. The DMATCR value will be
decremented for each transfer. The actual transfer flows vary by address mode and bus mode.
transfer ends normally. If the IE bit of the CHCR is set to 1 at this time, a DEI interrupt is sent
to the CPU. If the RPT bit is set to 1, the IAR value is set in SAR or DAR and DMATCR is
initialized to the written value. In this case, transfer can be continued only by clearing the TE
bit.
the DE bit of the CHCR or the DME bit of the DMAOR are changed to 0.
Operation
DMA Transfer Flow
Rev. 1.00, 02/04, page 313 of 804