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Hi,
I would like to change the packet size in the ISOC module (USBIsocSourceSink)
in the 'cyfxisosrcsink.h' I'm changing 'CY_FX_ISO_MAXPKT' parameter from 1024 to 225.
I'm successfully program the FX3 but the device isn't enumerated.
is there any other parameter I should change in order to change packet size?
Solved! Go to Solution.
- Tags:
- fx3,
- packet size
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Hello,
Please refer to Section 4.4.8 Isochronous Transfers, more specifically 4.4.8.1. which says about the ISOC endpoint size requirements in USB 3.1 Specification from the following link: https://manuais.iessanclemente.net/images/b/bc/USB_3_1_r1.0.pdf
This section explains about the ISOC endpoint usage and requirements in SS USB.
Regards,
Yashwant
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Hello,
Along with the CY_FX_ISO_MAXPKT set to 225, you will also need to change the CY_FX_ISO_BURST to (1) as shown below:
This will make the device enumerate properly with an endpoint size of 224.
Regards,
Yashwant
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thanks a lot!
and if I would like to change packet size to 1 byte? is it possible?
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Hello,
Yes, the packet size can be set to 1 Byte as well.
But to only get one packet of 1 Byte, you can set the Mult Setting CY_FX_ISO_PKTS to (1).
Regards,
Yashwant
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Great, thanks.
what is the theory behind the correlation between those different parameters :
1. max packets
2. ISOC packets
3. max burst size
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Hello,
Please refer to Section 4.4.8 Isochronous Transfers, more specifically 4.4.8.1. which says about the ISOC endpoint size requirements in USB 3.1 Specification from the following link: https://manuais.iessanclemente.net/images/b/bc/USB_3_1_r1.0.pdf
This section explains about the ISOC endpoint usage and requirements in SS USB.
Regards,
Yashwant