ISP1181BBSUM STEricsson, ISP1181BBSUM Datasheet - Page 20

• Manufacturer Part Number: ISP1181BBSUM
• Manufacturer: STEricsson

Specifications of ISP1181BBSUM

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 48
• Lead Free Status / RoHS Status: Compliant

11. Suspend and resume
CD00222684
Product data sheet
11.1 Suspend conditions
The ISP1181B detects a USB suspend status when a constant idle state is present on the
USB bus for more than 3 ms.
The bus-powered devices that are suspended must not consume more than 500 μA of
current. This is achieved by shutting down power to system components or supplying
them with a reduced voltage.
The steps leading up to suspend status are as follows:
Figure 6
1. On detecting a wake-up-to-suspend transition, the ISP1181B sets bit SUSPND in the
2. When the firmware detects a suspend condition, it must prepare all system
3. In the interrupt service routine, the firmware must check the current status of the USB
4. To meet the suspend current requirements for a bus-powered device, the internal
5. When the firmware has set and cleared bit GOSUSP in the Mode register, the
Interrupt register. This will generate an interrupt if bit IESUSP in the Interrupt Enable
register is set.
components for the suspend state:
a. All signals connected to the ISP1181B must enter appropriate states to meet the
b. All input pins of the ISP1181B must have a CMOS LOW or HIGH level.
bus. When bit BUSTATUS in the Interrupt register is logic 0, the USB bus has left the
suspend mode and the process must be aborted. Otherwise, the next step can be
executed.
clocks must be switched off by clearing bit CLKRUN in the Hardware Configuration
register.
ISP1181B enters the suspend state. In powered-off application, the ISP1181B asserts
output SUSPEND and switches off the internal clocks after 2 ms.
power consumption requirements of the suspend state.
shows a typical timing diagram.
Rev. 05 — 25 August 2010
Full-speed USB peripheral controller
© ST-ERICSSON 2010. All rights reserved.
ISP1181B
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