CHAPTER 6 DMA FUNCTIONS (DMA CONTROLLER)
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User’s Manual U14492EJ3V0UD
Figure 6-8. Buffer Register Configuration
The actual DMA transfer is performed based on the settings of the slave register.
The settings incorporated in the master and slave registers differ as follows according to the timing (time) at which
the settings were made.
(1) Time from system reset to the start of the first DMA transfer
The settings made are incorporated in both the master and slave registers.
(2) During DMA transfer (time from the start to end of DMA transfer)
The settings made are incorporated in only the master register, and not in the slave register (the slave
register maintains the value set for the next DMA transfer).
However, the contents of the master register are automatically overwritten in the slave register after DMA
transfer ends.
(3) Time from DMA transfer end to the start of the next DMA transfer
The settings made are incorporated in both the master and slave registers.
Remark
“DMA transfer end” means one of the following.
•
Completion of DMA transfer (terminal count)
•
Forcible termination of DMA transfer (the INITn bit of DMA channel control register n (DCHCn) is set
to 1)
Data read
Data write
Master
register
Slave
register
Address/
count
controller
Internal bus
Содержание V850E/IA1 mPD703116
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