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Posts: 992 | Thanked: 995 times | Joined on Dec 2009 @ California
#769
Originally Posted by blue_led View Post
from datasheet of 1704
"8.7.2.1 VBUS valid comparator
This comparator is used by hosts and A-devices to determine whether the voltage on
VBUS is at a valid level for operation. The ISP1704A minimum threshold for the VBUS valid
comparator is 4.4 V. Any voltage on VBUS below this threshold is considered invalid.
During power-up, it is expected that the comparator output will be ignored.'"


if otg controller expect a valid vbus on isp1704 vbus probe pin maybe this is the reason for timeouts
Hm-m... But it definitely transmits... Or it may be a comparator for validity check to supply a valid VBUS from 1707?

do a voltage check with a voltmeter . if vbus is below 3.3V this voltage come from isp1707 internals.
I don't think so - until I programmed TWL4030 I didn't see any VBUS voltage above VSESSVALID (0.8v - 1.4v) or in ARM CPU USB description - "Above session end, below AValid".

EDIT: "Above AValid, below VBusValid" - sorry for confusion, still sleepy.

Last edited by egoshin; 2010-05-07 at 17:17.
 

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