| Copyright © 2010-2011 ARM. All rights reserved. | ARM DDI 0460D |
| Non-Confidential | ID092411 |
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The processor offers functionality for debugging systems with energy-management capabilities. This section describes scenarios where the OS takes energy-saving measures when in an idle state.
The different measures that the OS can take to save energy during an idle state are divided into two groups:
The OS takes measures that reduce energy consumption but maintain the processor state.
The OS takes measures that reduce energy consumption but do not maintain the processor state, for example, Dormant or Shutdown mode. Recovery involves a reset of the processor after the power level has been restored, and reinstallation of the processor state.
Standby is the least invasive OS energy-saving state because it only implies that the core is unavailable. It does not clear any of the debug settings. For this case, the processor offers the following:
If the processor is in standby and a halting debug event occurs, the processor:
leaves standby
retires the Wait-For-Interrupt (WFI)
or Wait-For-Event (WFE)
instruction
enters debug state.
If the processor is in standby and detects an APB port access, it temporarily leaves standby state to complete the transaction. While the processor wakes up from standby, the APB access is held by keeping the PREADYDBGm signal LOW.
| Copyright © 2010-2011 ARM. All rights reserved. | ARM DDI 0460D |
| Non-Confidential | ID092411 |
| PDF version | |
| Home > Debug > Debugging systems with energy management capabilities |