ISP1160
Embedded USB Host Controller
Philips Semiconductors
XOSC_6MHz
HC_ClkOk
PLL_Lock
HC PLL
PLL_ClkOut
DIGITAL
CLOCK
SWITCH
XOSC
On
HC_Clk48MOut
HC_RawClk48M
On
On
HC
CORE
HC_EnableClock
HcHardware Configuration
bit 11 (SuspendClkNotStop)
On
HC_NeedClock
VOLTAGE
REGULATOR
H_WAKEUP (pin)
CS_N (pin)
004aaa375
Fig 28. ISP1160 suspend and resume clock scheme.
In the suspended state, the device will consume considerably less power by turning
off the internal 48 MHz clock, PLL and crystal, and setting the internal regulator to
power-down mode. The ISP1160 suspend and resume clock scheme is shown in
Figure 28.
Pin H_SUSPEND is the sensing output pin for the HC’s suspended state. When the
HC goes into the USBSuspend state, this pin will output a HIGH level (logic 1). This
pin is cleared to LOW (logic 0) level only when the HC is put into a USBReset state or
USBOperational state (refer to the HcControl register bits 7 to 6; 01H to read, 81H to
write). Bit 11, SuspendClkNotStop, of the HcHardwareConfiguration register (20H to
read, A0H to write), defines if the HC internal clock is stopped or kept running when
the HC goes into the USBSuspend state. After the HC enters the USBSuspend state
for 1.3 ms, the internal clock will be stopped if bit SuspendClkNotStop is logic 0.
For details on power consumption, refer to Philips Application Note
AN10022 ISP1160x Low Power Consumption.
9.9.2 HC wake-up from suspended state
There are three methods to wake up the HC from the USBSuspend state: hardware
wake-up, software wake-up, and USB bus resume. They are described as follows.
Wake-up by pin H_WAKEUP: Pins H_SUSPEND and H_WAKEUP provide
hardware wake-up, a way of remote wake-up control for the HC without the need to
access the HC internal registers. H_WAKEUP is an external wake-up control input
pin for the HC. After the HC goes into the USBSuspend state, it can be woken up by
sending a HIGH level pulse to pin H_WAKEUP. This will turn on the HC’s internal
clock, and set bit 6, ClkReady, of the HcµPInterrupt register (24H to read, A4H to
write). Under the USBSuspend state, once pin H_WAKEUP goes HIGH, after 160 µs,
the internal clock will be up. If pin H_WAKEUP continues to be HIGH, then the
internal clock will be kept running, and the microprocessor can set the HC into
USBOperational state during this time. If H_WAKEUP goes LOW for more than
1.14 ms, the internal clock stops and the HC goes back into the USBSuspend state.
9397 750 11371
© Koninklijke Philips Electronics N.V. 2003. All rights reserved.
Product data
Rev. 04 — 04 July 2003
35 of 88
NXP [ NXP ]
