Книга: Microsoft Windows Embedded CE 6.0 Exam Preparation Kit
Supporting the Critical Off State
Supporting the Critical Off State
On hardware platforms equipped with a voltage comparator that triggers NMI, you can implement support for the Critical Off state to protect the user from data loss in low-battery conditions. On x86 hardware, the kernel exports the OEMNMIHandler function to capture critical events in the system. On other systems, you might have to implement a custom IST that calls SetSystemPowerState to turn off the system gracefully with the help of Power Manager. The Critical Off state typically corresponds to the Suspend state with dynamic RAM refresh enabled.
NOTE
Battery level reaches zero
When implementing Critical Off state support, make sure you trigger the NMI at a point when the system still has time to perform all power down tasks , such as powering down peripherals, putting RAM into self-refresh, perhaps setting a wakeup condition, and suspending the CPU.
Оглавление книги
- 4.4.4 The Dispatcher
- About the author
- Chapter 7. The state machine
- Appendix E. Other resources and links
- Example NAT machine in theory
- The final stage of our NAT machine
- Compiling the user-land applications
- The conntrack entries
- User-land states
- Untracked connections and the raw table
- Basics of the iptables command
- State match