NO:
W90P710 Programming Guide
VERSION:
2.1
PAGE:
65
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
In this example, source base address is set as 0xC2000000 and destination base address is
0xC2001000. The transfer count is 0x10. The burst mode is not turned on in this example.
Both source and destination base addresses are increment. The transfer width is 32-bit. The
program waits GDMA transfer completed by polling TC flag. The first line of main routine that clears
the GDMA control register is used to avoid that the SOFTREQ did not be self-cleared in the previous
GDMA transfer. Once these code executed, the GDMA will copy 0x10*4 bytes data from 0xC2000000
to 0xC2001000.
After the transfer completed, the current source, destination, and transfer count status can be
read from current status registers. These current status registers are GDMA_CSRC, GDMA_CDST,
and GDMA_CTNT respectively. However, if the AUTOIEN is 1, the current status registers will be
updated to the value stored in GDMA_SRCB, GDMA_DSTB, and GDMA_TCNT. The GDMAEN did
not be self-cleared if AUTOIEN is 1. Therefore, it only needs to set SOFTREQ to request the GDMA
transfer next time if the AUTOIEN is 1 by the same source address, destination address, and transfer
count.
5.4.5 GDMA operation started by nXDREQ
The GDMA can accept the request from external device. The external device requests the GDMA
transfer by asserting signal nXDREQ. When nXDREQ is used to request the GDMA transfer, it is
called external nXDREQ mode. The programming method of external nXDREQ mode is the same as
software mode except for the followings.
•
The GDMA transfer is requested by nXDREQ pin.
•
The GDMA is operated in external nXDREQ mode (GDMANS=01b).
•
Single mode is valid.
•
Demand mode is valid.