
CHAPTER 6 DMA FUNCTIONS (DMA CONTROLLER)
User’s Manual U12688EJ4V0UM00
191
6.10 DMA Transfer Start Factors
There are 3 types of DMA transfer start factors, as shown below.
(1) Request from an external pin (DMARQn)
Although requests from the DMARQn pin are sampled each time the CLKOUT signal falls, sampling should
be continued until the DMAAKn signal becomes active (n = 0 to 3).
If a state in which the ENn bit of the DCHCn register = 1 and the TCn bit = 0 is set, the DMARQn signal in the
T1 state becomes active. If the DMARQn signal becomes active in the T1 state, it changes to the T0 state
and DMA transfer starts.
(2) Request from software
If the STGn, ENn and TCn bits of the DCHCn register are set as follows, DMA transfer starts (n = 0 to 3).
•
STGn bit = 1
•
ENn bit = 1
•
TCn bit = 0
(3) Request from internal peripheral I/O
If, when the ENn and TCn bits of the DCHCn register are set as shown below, an interrupt request is issued
from the internal peripheral I/O that is set in the DTFRn register, DMA transfer starts (n = 0 to 3).
•
ENn bit = 1
•
TCn bit = 0
Содержание V850E/MS1 UPD703100
Страница 2: ...User s Manual U12688EJ4V0UM00 2 MEMO ...
Страница 6: ...User s Manual U12688EJ4V0UM00 6 MEMO ...
Страница 8: ...User s Manual U12688EJ4V0UM00 8 MEMO ...
Страница 12: ...User s Manual U12688EJ4V0UM00 12 MEMO ...
Страница 26: ...User s Manual U12688EJ4V0UM00 26 MEMO ...
Страница 68: ...User s Manual U12688EJ4V0UM00 68 MEMO ...
Страница 124: ...User s Manual U12688EJ4V0UM00 124 MEMO ...
Страница 198: ...User s Manual U12688EJ4V0UM00 198 MEMO ...
Страница 230: ...User s Manual U12688EJ4V0UM00 230 MEMO ...
Страница 422: ...User s Manual U12688EJ4V0UM00 422 MEMO ...