Difference between revisions of "83Plus:Software:usb8x/Asm Interface/FindDescriptor"
From WikiTI
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jp c,Error | jp c,Error | ||
ld b,descEndpoint | ld b,descEndpoint | ||
| − | call FindDescriptor ;Search for endpoint descriptor within config descriptor | + | call FindDescriptor ;Search for endpoint descriptor within config descriptor</nowiki> |
| − | </nowiki> | + | |
== See Also == | == See Also == | ||
* [[../ReadDescriptor|ReadDescriptor]] - Reads a descriptor from device | * [[../ReadDescriptor|ReadDescriptor]] - Reads a descriptor from device | ||
Revision as of 22:06, 15 July 2006
Synopsis
Name: FindDescriptor
Minimum usb8x version: 0.05
Find the first instance of a descriptor entry in the config descriptor listing
Inputs
- B: Descriptor type
- HL: Address of descriptor list
Outputs
- DE: Points byte after entire descriptor listing
- HL: Points to requested descriptor
- NC: Success
Destroys
- AF, BC
Notes
This routine only finds the first instance of a descriptor. There is an internal routine to find additional instances, but it does not currently have an entry point. This will be fixed in future versions.
Example
ld hl,DescriptorBuf ;Temporary buffer to hold config descriptor ld b,descConfig push hl call ReadDescriptor ;Read config descriptor from device pop hl jp c,Error ld b,descEndpoint call FindDescriptor ;Search for endpoint descriptor within config descriptor
See Also
- [[../ReadDescriptor|ReadDescriptor]] - Reads a descriptor from device
