XMC 4x00: Automatic SPI transfer with Transfer Control Information

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User14604
Level 4
Level 4
First solution authored
Hello devs,

I'm interfacing an SPI-connected ADC chip to retrieve AD channel data from it.
Therefore I sent 2 transfers of 32 bit each to simultaenously receive 2x 32 bit. Each transfers starts with a chip select assertion and stops with chip select de-assertion.

Unfortunately the SPI speed cannot be increased above 5 MHz. TX/RX of whole 64 bits currently takes ~20 us. I'd rather use that time to perfom other operations than to wait for the data to become sent/received.
I though about using FIFO / DMA-driven transfer.

1. If using FIFO, can I prepare the FIFO once and send it again and again without the need to refill the TX FIFO? Is it possible to also add TCI (Transfer Control Information) then?
2. If using DMA-driven transfer, am I able to add TCI to the TX data so that chip select lines are correctly pulled?

Best regards,
Ernie T
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1 Solution
LinglingG_46
Moderator
Moderator
Moderator
500 solutions authored 1000 replies posted 10 questions asked

 Is it possible to also add TCI (Transfer Control Information) then? If using DMA-driven transfer, am I able to add TCI to the TX data so that chip select lines are correctly pulled?

No.

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3 Replies
LinglingG_46
Moderator
Moderator
Moderator
500 solutions authored 1000 replies posted 10 questions asked
1. If using FIFO, can I prepare the FIFO once and send it again and again without the need to refill the TX FIFO?
No.

2. Is it possible to also add TCI (Transfer Control Information) then? If using DMA-driven transfer, am I able to add TCI to the TX data so that chip select lines are correctly pulled?
why do you want to use the TCI(Transfer Control Information)? The driver we provided has already set this situation.
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User14604
Level 4
Level 4
First solution authored
Thank you for reply, GLLing.

About 2: I'd like to have put two transfers into the DMA buffer and have it transferred one after another. I'm not sure whether your answer was a "yes" or "no".
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LinglingG_46
Moderator
Moderator
Moderator
500 solutions authored 1000 replies posted 10 questions asked

 Is it possible to also add TCI (Transfer Control Information) then? If using DMA-driven transfer, am I able to add TCI to the TX data so that chip select lines are correctly pulled?

No.

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