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Hello ,
I am trying to change the maximum packet size of my IN endpoint to 256 bytes using the dscr.a51 in High speed config dscr:
HighSpeedConfigDscr:
db DSCR_CONFIG_LEN ;; Descriptor length
db DSCR_CONFIG ;; Descriptor type
db (HighSpeedConfigDscrEnd-HighSpeedConfigDscr) mod 256 ;; Total Length (LSB)
db (HighSpeedConfigDscrEnd-HighSpeedConfigDscr) / 256 ;; Total Length (MSB)
db 1 ;; Number of interfaces
db 1 ;; Configuration number
db 0 ;; Configuration string
db 10100000b ;; Attributes (b7 - buspwr, b6 - selfpwr, b5 - rwu)
db 50 ;; Power requirement (div 2 ma)
;; Interface Descriptor
db DSCR_INTRFC_LEN ;; Descriptor length
db DSCR_INTRFC ;; Descriptor type
db 0 ;; Zero-based index of this interface
db 0 ;; Alternate setting
db 1 ;; Number of end points
db 0ffH ;; Interface class
db 00H ;; Interface sub class
db 00H ;; Interface sub sub class
db 0 ;; Interface descriptor string index
;; Endpoint Descriptor
db DSCR_ENDPNT_LEN ;; Descriptor length
db DSCR_ENDPNT ;; Descriptor type
db 82H ;; Endpoint number, and direction
db ET_BULK ;; Endpoint type
db 00H ;; Maximum packet size (LSB)
db 01H ;; Maximum packet size (MSB)
db 00H ;; Polling interval
But when i transmit the packets it hits abort pipe after few data transfers
Why is it happenning could someone explain?
thanks and regards
Solved! Go to Solution.
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Hi,
This is because the max size of an endpoint is USB specification defined parameter. You can not change the endpoint size (max packet size) of a device.
Regards,
Mallika
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Originally the max packet size is 512 bytes
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Hi,
This is because the max size of an endpoint is USB specification defined parameter. You can not change the endpoint size (max packet size) of a device.
Regards,
Mallika