cancel
Showing results for 
Search instead for 
Did you mean: 

Knowledge Base Articles

To know the inserted device is Full speed or low speed when SL811 is host

Anonymous
Not applicable

To know the inserted device is Full speed or low speed when SL811 is host

Answer:

Question: When using the SL811HS in host mode, how can you tell when a device is inserted, and whether it is full or low speed?

Response: When using the SL811HS in host mode, you can monitor devices being inserted or removed from the Insterrupt Status Register [0DH].

The Interrupt Status Register provides 3 bits (bits 5, 6, and 7) to properly monitor devices being inserted and removed.  Below are general guidelines of how to use these bits.

1) First, monitor the Insert/Remove bit (bit 5).  The bit will get asserted when a device is either inserted (bus state goes from SE0 to IDLE) or removed ( bus state goes from IDLE to SE0).

2) If the Insert/Remove bit is asserted, then you need to determine which of the two events happened.  The Device Detect/Resume bit (bit 6), is used to indicate the presense of a device, '1' = device "Not present" and '0' = device "Present".

Be aware that this bit is shared between Device detection status and a Resume detection interrupt.  When bit 6 of register 05H is set to one, this bit will be the Resume detection interrupt bit.  Otherwise, this bit

3) Once it has been established from both bits 5 and 6 that a device has been inserted, the D+ bit (bit 7) will indicate whether it is a full speed device or not.  If D+ is high, then the D+ line is pulled up and a full speed device is plugged in, otherwise D- is low and a low speed device was plugged in.


0 Likes
Version history
Revision #:
1 of 1
Last update:
‎Dec 19, 2008 12:00 AM
Updated by:
Anonymous
 
Contributors