Rainbow Electronics W90P710CDG - Manual (Page 164)

W90P710CD/W90P710CDG
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Continued
BITS DESCRIPTIONS
[19] AUTOIEN
Auto initialization Enable
1’b0 = Disables auto initialization
1’b1 = Enables auto initialization, the GDMA_CSRC0/1,
GDMA_CDST0/1,and GDMA_CTCNT0/1 registers are updated by the
GDMA_SRC0/1,GDMA_DST0/1,and GDMA_TCNT0/1 registers
automatically when transfer is complete.
[18] TC
Terminal Count
1’b0 = Channel does not expire
1’b1 = Channel expires; this bit is set only by GDMA hardware, and clear
by software to write logic 0.
TC [18] is the GDMA interrupt flag. TC [18] or GDMATERR[20] will
generate interrupt
[17] BLOCK
Bus Lock
1’b0 = Unlocks the bus during the period of transfer
1’b1 = Locks the bus during the period of transfer
[16] SOFTREQ
Software Triggered GDMA Request
Software can request the GDMA transfer service by setting this bit to 1.
This bit is automatically cleared by hardware when the transfer is
completed. This bit is available only while GDMAMS [3:2] register bits are
set on software mode (memory to memory).
[15] DM
Demand Mode
1’b0 = Normal external GDMA mode
1’b1 = When this bit is set to 1, the external GDMA operation is speeded
up. When external GDMA device is operating in the demand mode, the
GDMA transfers data as long as the external GDMA request signal
nXDREQ is active. The amount of data transferred depends on how long
the nXDREQ is active. When the nXDREQ is active and GDMA gets the
bus in Demand mode, DMA holds the system bus until the nXDREQ
signal becomes non-active. Therefore, the period of the active nXDREQ
signal should be carefully tuned such that the entire operation does not
exceed an acceptable interval (for example, in a DRAM refresh
operation).
[14] Reserved -