JAJSP77A November 2019 – August 2020 BQ79600-Q1
PRODUCTION DATA
Sniff detector is only used if reverse wakeup feature is used.
Sniff detector, powered by AVAOREF, is used to detect fault tone from stack device on COMH* or COML*. This detector would trigger if it detects/counts no less than nVALIDATE of continuous couplets (either “-” or “+”) with amplitude larger than VVAL_THR. If any couplet timing interval is larger than tSNIFFIDLE, detector/counter is reset.
This sniff detector rejects HB tone since nVALIDATE is more than 30, both HB/Fault tone are “-” tone; detector doesn’t expect “+” tone.
The usage assumption of this detector is when system is in idle mode, BQ79600-Q1 in SHUTDOWN.
Sniff detector is only effective in SHUTDOWN. Once detector is triggered, device transitions from SHUTDOWN to VALIDATE. The sniff detector is by default disabled when first transition from COMPLETE OFF to SHUTDOWN. To enable the feature, host has to keep [SNIFDET_EN] = ‘1’ & [SNIFDET_DIS] = ‘0’ before transitioning to SHUTDOWN. After enabling the detector, if device doesn’t transition to COMPLETE OFF, the only way to disable the detector is to keep [SNIFDET_DIS] = ‘1’. (Disable bit has higher priority so don’t care about the setting of [SNIFDET_EN]) before transitioning to SHUTDOWN.)