How can I use API about spi.write()

Mbed OS
1

Hi
I want to ask how to use the API about spi.write() below.

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Now I only can use spi.write(0xff) to controll the SPI transaction.
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But if I want to use another spi.write()API, it would show the error below.
Can you help me with how to use this API correctly?
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2

Hello,

that is probably because your both buffers are Int type, so check the requested data types of SPI::write(…). I see const char pointer and char pointer.

BR, Jan

3

Hi Jan,

Thank you for your information!
But according to my experiment, I still cannot use API spi.write() successfully after I select the requested data types.
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Can you help me how to define the requested data successfully?
Thank you !

Best Regards,
Denny

4

Hello,

probably go back to your previous version and just change from int type to char type

Br, Jan

5

spi.write accepts pointers to char arrays. You should still declare them as char tx[2] and char rx[2], and simply invoke spi.write(tx, 2, rx, 2).

6

Hi Jan,

It seems to work successfully when using “char” type.
Thank you so much for your help!

Best Regards,
Denny

7

Hi Richard,

It helps me a lot and I work successfully by using “char” type.
Thank you so much!

Best Regards,
Denny

8

Adding a short explanation:

char RxBuf[2]; creates a char pointer with the name RxBuf.
Thats the reason why just usign char solved the issue.

Same reasoning for const char* TxBuf[2]