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annotate rtc.h @ 31:03592ca4d37e

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Port tempctrl.c from AVR. I removed the beep code as I don't have a beeper on the STM32 board. Reworked the heat/cool stuff so it can use separate ports.
author Daniel O'Connor <darius@dons.net.au>
date Tue, 27 Nov 2012 13:20:52 +1030
parents 435c6330896c
children
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435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
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1 /* RTC period = RTCCLK/RTC_PR = (32.768 KHz)/(32767+1) */
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
2 #define RTC_PRESCALE 32768
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
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3
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
4 /* usec = x * 1e6 / 32768
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
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5 * However, 1e6 / 32768 = 30.5 which will result in a large error (max of 15807 usec), so we use
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
6 * some extra bits to get more precision. We can scale up until 32768 * n is > 2^32.
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
7 * This results in a maximum error of 1 usec.
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
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8 */
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
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9 #define RTC_PS2USEC(x) ( \
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
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10 (uint32_t)( \
435c6330896c Set tv_usec in gettimeofday() by using the prescaler counter.
Daniel O'Connor <darius@dons.net.au>
parents:
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11 (uint32_t)((1 << 9) * (1e6 / RTC_PRESCALE)) * (RTC_PRESCALE - (x))) >> 9)