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CSK10
Level 3
Level 3
First like received First like given 50 sign-ins

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

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1 Solution
MallikaK_22
Moderator
Moderator
Moderator
50 likes received 750 replies posted 250 solutions authored

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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2 Replies
CSK10
Level 3
Level 3
First like received First like given 50 sign-ins

Originally the max packet size is 512 bytes 

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MallikaK_22
Moderator
Moderator
Moderator
50 likes received 750 replies posted 250 solutions authored

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

0 Likes