upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 514

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

Remark:
514
(DMA channel 0 )
(DMA channel 0)
(DMA channel 3)
(DMA channel 3)
DMBC0 = 02H (3-times transfer)
DMBC3 = 03H (4-times transfer)
Bus status
ACF
DMARQ0
DMARQ3
0
1
ACF
ACF
EN
EN
TC = Transfer Count achieved
No DMA transfer in progress.
Indicate the DMA transfer status.
When ACF is set (1), the state is different depending on the transfer mode.
Single or Fixed Channel transfer mode:
DMA transfer has been executed at least one time, but the total number of transfers has not yet
been reached.
If other channels of DMA transfer are occurring, the non-corresponding ACF bit will be cleared.
Block transfer mode:
At least one DMA transfer has been executed, but further transfers are pending as the total num-
bers of transfers not yet reached.
In Block Transfer mode, the CPU can not access the ACF bit during the transfer. If a NMI inter-
rupt occurs during a block transfer mode, then the ACF bit will be read by CPU as an “1”.
Figure 15-10: DMA Channel Control Register (DMCHCn) Format (2/4)
Set to 1 by Software
Set to 1 by Software
CPU
CPU
Chapter 15 DMA Functions (DMA Controller)
CPU
(a) ACF bit status in single transfer mode
DMA3
User’s Manual U16702EE3V2UD00
CPU
DMA3
DMA Acknowledge Flag
CPU
DMA0
CPU
D
CPU
DMA3
TC
CPU
DMA0
CPU
DMA0
TC
CPU