1.2.7 1.6.9 1.7.10 1.8.6 1.9.6 1.32.10 1.34.4 1.35.3 1.36.5 1.42.2 Data Watchpoint and Trace (DWT)
Data Watchpoint and Trace (DWT) peripheral can be configured as a hardware watchpoint. The first comparator DWT_COMP0 can also compare against the clock cycle counter CYCCNT.
The DWT if present contains counters for:
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Clock cycles (CYCCNT)
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Folded instructions
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Load Store Unit (LSU) operations
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Sleep cycles
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CPI, that is all instruction cycles except for the first cycle
Using The Library
A DWT contains one comparator that you can use as a watchpoint and Cycle matching functionality is available in comparator 0.
int main(void) { /* Initialize all modules */ SYS_Initialize ( NULL ); /* Generate 1000 ms delay using DWT */ DWT_DelayMs(1000); }
Library Interface
Data Watchpoint and Trace peripheral library provides the following interfaces:
Functions
| Name | Description |
|---|---|
| DWT_Initialize | Initializes Data Watchpoint and Trace (DWT) unit |
| DWT_DelayUs | Blocking function to generate delay in microseconds |
| DWT_DelayMs | Blocking function to generate delay in milliseconds |
| DWT_CounterReset | Reset the cycle counter Value |
| DWT_CounterEnable | Enable the cycle counter |
| DWT_CounterDisable | Disable the cycle counter |
| DWT_CounterGet | Get the cycle counter current Value |