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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2011-10-03 12:21:20 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2011-10-03 12:21:20 +0000 |
commit | 459c337817e461bc5aed4d14fab869e7d699b6f1 (patch) | |
tree | 4c0d7f6d3cc19316ac79767b000f7005c442d015 /nuttx/configs/stm3210e-eval | |
parent | 5246751cb564522530b70b4f171dbd3d09a6eb4b (diff) | |
download | px4-nuttx-459c337817e461bc5aed4d14fab869e7d699b6f1.tar.gz px4-nuttx-459c337817e461bc5aed4d14fab869e7d699b6f1.tar.bz2 px4-nuttx-459c337817e461bc5aed4d14fab869e7d699b6f1.zip |
Restore CLOCK_ACTIVETIME
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4009 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/configs/stm3210e-eval')
-rwxr-xr-x | nuttx/configs/stm3210e-eval/README.txt | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/nuttx/configs/stm3210e-eval/README.txt b/nuttx/configs/stm3210e-eval/README.txt index 3f260e9a8..f82c2243b 100755 --- a/nuttx/configs/stm3210e-eval/README.txt +++ b/nuttx/configs/stm3210e-eval/README.txt @@ -14,6 +14,7 @@ Contents - DFU - LEDs - Temperature Sensor + - RTC - STM3210E-EVAL-specific Configuration Options - Configurations @@ -264,6 +265,38 @@ commands enumerated in include/nuttx/sensors/lm75.h. Also read the descriptions of the stm32_lm75initialize() and stm32_lm75attach() interfaces in the arch/board/board.h file (sames as configs/stm3210e-eval/include/board.h). +RTC +=== + + The STM32 RTC may configured using the following settings. + + CONFIG_RTC - Enables general support for a hardware RTC. Specific + architectures may require other specific settings. + CONFIG_RTC_HIRES - The typical RTC keeps time to resolution of 1 + second, usually supporting a 32-bit time_t value. In this case, + the RTC is used to "seed" the normal NuttX timer and the + NuttX timer provides for higher resoution time. If CONFIG_RTC_HIRES + is enabled in the NuttX configuration, then the RTC provides higher + resolution time and completely replaces the system timer for purpose of + date and time. + CONFIG_RTC_FREQUENCY - If CONFIG_RTC_HIRES is defined, then the + frequency of the high resolution RTC must be provided. If CONFIG_RTC_HIRES + is not defined, CONFIG_RTC_FREQUENCY is assumed to be one. + CONFIG_RTC_ALARM - Enable if the RTC hardware supports setting of an alarm. + A callback function will be executed when the alarm goes off + + In hi-res mode, the STM32 RTC operates only at 16384Hz. Overflow interrupts + are handled when the 32-bit RTC counter overflows every 3 days and 43 minutes. + A BKP register is incremented on each overflow interrupt creating, effectively, + a 48-bit RTC counter. + + In the lo-res mode, the RTC operates at 1Hz. Overflow interrupts are not handled + (because the next overflow is not expected until the year 2106. + + WARNING: Overflow interrupts are lost whenever the STM32 is powered down. The + overflow interrupt may be lost even if the STM32 is powered down only momentarily. + Therefore hi-res solution is only useful in systems where the power is always on. + STM3210E-EVAL-specific Configuration Options ============================================ |