If the SPI interface has a 16-bit interface then you should do an A-sync transfer with ACNT=2. It should be A-sync and not AB-sync because the SPI interface is only ready to receive one element when it gives the “ready” signal to the EDMA. If for example the SPI had a FIFO on it then you would be able to do AB-sync with BCNT equal to the FIFO depth, but that’s not the case.
The BIDX is the src/dst pointer post-increment used after transferring ACNT bytes (i.e. an array). The CIDX is the src/dst pointer post increment used after transferring BCNT arrays (i.e. a frame). Note that CIDX is measured differently depending on whether you are doing A-sync or AB-sync transfers. If CCNT=1 (which will probably be the case for you) then the CIDX is a don’t care. Also, remember that the total number of bytes transferred is ACNT*BCNT*CCNT so don’t make CCNT=0 or else nothing at all will transfer! Brad ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Winston Ma Sent: Sunday, April 06, 2008 10:13 PM To: [email protected] Subject: SPI over EDMA settings Dear all, I would like to know what types of transfer I should use? A-Synchronized or AB-Synchronized? also what is the BIDX and CIDX settings? Thanks a lot ________________________________ 出差或去旅遊時，你可以隨時隨地用全新的 Yahoo! Messenger 網上版 <http://hk.webmessenger.yahoo.com/> 跟你的朋友即時通訊及查詢對話訊息紀錄!
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