Patent ID: 8008949

Claim:
A clock selector operative with a communications processor requiring a system clock, the clock selector selecting between an intermittently available first host clock for use by the communications processor in a non-wireless operational mode for the buffering of packets through a host interface and an intermittently available second network clock for use by the communications processor in a wireless operational mode for transmitting or receiving packets, the communication processor wireless operational mode including the operation of a wireless transmitter/receiver having higher power consumption than said communication processor non-wireless operational mode where the wireless transmitter/receiver is inactive, the communications processor also having a third continuously available sleep clock for a sleep mode having lower power consumption than said non-wireless operational mode or said wireless operational mode, said clock selector operative on a SELECT input, said communications processor having: a sleep state machine operative from said third sleep clock and in communication with a host interface controller, said sleep state machine generating a DIS_NETCLK signal for disabling said second network clock, said sleep state machine also generating a NETCLK_OFF signal indicating when said second network clock is inactive; said host interface controller receiving said first host clock when active and indicating when packets are to be received or transmitted to said host interface, said host interface controller indicating the availability of said host clock when said first host clock is active, said host clock being inactive at other times; said second network clock inactive and disabled by said DIS_NETCLK signal when asserted, said DIS_NETCLK not asserted and said second network clock active when said communications processor wireless interface is transmitting or receiving packets; said SELECT input responsive to said host clock availability and also said NETCLK_OFF, thereby causing said clock selector to select said host clock when said host clock is available and selecting said network clock when said host clock is not available and said NETCLK_OFF is not asserted.