Epson S1C33210 - Manual (Page 499)

V DMA BLOCK: IDMA (Intelligent DMA)
S1C33210 FUNCTION PART EPSON B-V-3-11
Processing of interrupt factors by type of trigger
• When invoked by an interrupt factor
The interrupt factor flag by which IDMA has been invoked remains set even during a DMA transfer.
If the transfer counter is decremented to 0 and DINTEN = "1" (interrupt enabled) when one DMA transfer is
completed, the interrupt factor that has invoked IDMA is not reset and an interrupt request is generated. At the
same time, the IDMA request register is cleared to "0". The IDMA enable bit is not cleared and remains set to
"1".
If the transfer counter is not 0, the interrupt factor flag is reset when the DMA transfer is completed, so that no
interrupt is generated. In this case, the IDMA request bit and IDMA enable bit are not cleared and remain set to
"1".
When DINTEN has been set to "0" (interrupt disabled), the interrupt factor flag is reset even if the transfer
counter reaches 0, so that no interrupt is generated. In this case, the IDMA request bit is not cleared but the
IDMA enable bit is cleared.
2 1 0
Trigger by interrupt factor
Data transfer
Transfer counter
DINTEN
IDMA request bit
IDMA enable bit
Interrupt factor flag
Interrupt request
1 0
Figure 3.4 Operation when Invoked by Interrupt Factor
When IDMA is invoked by the software trigger, the IDMA interrupt factor flag FIDMA (D4)/DMA interrupt
factor flag register (0x40281) will not be set.
• When invoked by a software trigger
If the transfer counter is decremented to 0 and DINTEN = "1" (interrupt enabled) when one DMA transfer is
completed, the IDMA interrupt factor flag FIDMA (D4)/DMA interrupt factor flag register (0x40281) is set,
thereby generating an interrupt request.
If the transfer counter is not 0 or DINTEN = "0" (interrupt disabled), the FIDMA flag is not set.
If the interrupt factor flag for the same channel is set during a software-triggered transfer, the IDMA
invocation request by that interrupt factor flag is kept pending. However, the interrupt factor flag will be reset
when the current execution is completed, so there will be no DMA transfer by the interrupt factor flag.
2 1 0
Software trigger
Data transfer
Transfer counter
DINTEN
FIDMA (D4/0x40281)
Interrupt request
1 0
Figure 3.5 Operation when Invoked by Software Trigger