NO:
W90P710 Programming Guide
VERSION:
2.1
PAGE:
66
The above information is the exclusive intellectual property of Winbond Electronics and shall not be disclosed,
distributed or reproduced without permission from Winbond.
Table No.: 1200-0003-07-A
5.4.6 Fixed Address
Generally the GDMA continually increase or decrease the source and destination address during
data transfer. The W90P710 GDMA controller provides another feature to support the fixed
source/destination address to perform data transfer between system memory and external device. To
do a Memory-to-I/O transfer, the bit
DAFIX
in register GDMA_CTL should be set. In case of I/O-to-
Memory transfer, the bit
SAFIX
in register GDMA_CTL should be set.
5.4.7 Block Mode Transfer
When GDMA is programmed to block mode (
[SBMS]
= 1), it needs only one request to transfer
all the data. When receiving
nXDREQ
request or the bit
SOFTREQ
is set, the GDMA begins to
transfer data. After the numbers of data specified on register
GDMA_TCNT
have been transferred,
the GDMA set the bit
TC
and generates an interrupt if it is enabled. Then the GDMA stops until next
request is received.
5.4.8 Single Mode Transfer
The single mode transfer (
[SBMS]
= 0) is different to block mode. It can’t be started via setting bit
SOFTREQ. Besides, Single Mode Transfer requires an
nXDREQ
request for each data transfer that
may be one byte, one-halftword, or one word. When receiving
nXDREQ
request, GDMA performs a
single data transfer and then wait for next
nXDREQ
. After the numbers of data specified by register
GDMA_TCNT
have been transferred, the GDMA set the bit
TC
and generates an interrupt if it is
enabled.
5.4.9 Demand Mode Transfer
The GDMA controller supports the demand mode feature to speed up external DMA transfer.
When bit
DM
of register GDML_CTL is set to 1, GDMA controller transfers data as long as the signal
nXDREQ is active. The amount of data transferred depends on how long the nXDREQ is active.