upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 515

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

(DMA channel 0)
(DMA channel 3)
(DMA channel 0)
(DMA channel 3)
DMBC0 = 02H (3-times transfer)
DMBC3 = 03H (4-times transfer)
DMBC0 = 02H (3-times transfer)
DMBC3 = 03H (4-times transfer)
Bus status
DMARQ0
DMARQ3
(DMA channel 3)
(DMA channel 0)
(DMA channel 0)
(DMA channel 3)
ACF
ACF
EN
EN
Bus status
Figure 15-10: DMA Channel Control Register (DMCHCn) Format (3/4)
DMARQ0
DMARQ3
Set to 1 by Software
Set to 1 by Software
ACF
ACF
In this example, the internal bus is occupied by the DMA during these times.
Due to this behavior, the ACF bit during these times cannot be read by the CPU.
If a NMI interrupt occurs during a block transfer mode, then the ACF bit will be read by CPU as an “1”.
CPU
EN
EN
(b) ACF bit status in channel-fixed single transfer mode
Set to 1 by Software
CPU
Set to 1 by Software
CPU
Chapter 15 DMA Functions (DMA Controller)
CPU
(c) ACF bit status in block transfer mode
CPU
User’s Manual U16702EE3V2UD00
DMA3
CPU
CPU
DMA3
DMA3
DMA3 DMA3 DMA3
CPU
DMA3
TC
CPU
CPU
DMA3
CPU
TC
CPU
DMA0
DMA0
DMA0 DMA0
CPU
DMA0
TC
CPU
CPU
CPU
DMA0
TC
CPU
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