LeafLabs Garden » Topic: Maple Real-time clock implementation

LeafLabs Garden » Topic: Maple Real-time clock implementation http://forums.leaflabs.com/topic.php?id=1499 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:18:18 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://forums.leaflabs.com/search.php gbulmer on "Maple Real-time clock implementation" http://forums.leaflabs.com/topic.php?id=1499#post-20412 Mon, 22 Oct 2012 12:35:43 +0000 gbulmer 20412@http://forums.leaflabs.com/ aaronmatt - your post contained a link to an irrelevant site, and hence looks like spam, so it has been deleted. Further, your comment is incorrect. The Real-Time clock described on this thread is built into the STM32F1xx, and is not external on a computer motherboard. Anonymous on "Maple Real-time clock implementation" http://forums.leaflabs.com/topic.php?id=1499#post-20408 Mon, 22 Oct 2012 05:15:09 +0000 Anonymous 20408@http://forums.leaflabs.com/ A real-time clock is a battery-powered clock that is included in a microchip in a computer motherboard.. This project can be used to set and read the RTC.. Thanks for this nice post.. ___________________________________________ Edit: removed spam-like link gbulmer on "Maple Real-time clock implementation" http://forums.leaflabs.com/topic.php?id=1499#post-10064 Mon, 02 Apr 2012 06:39:13 +0000 gbulmer 10064@http://forums.leaflabs.com/ There has been quite a lot of discussion about external real time clocks. I think this talked about some advantages of external RTC <a href="http://forums.leaflabs.com/topic.php?id=103&page=2#post-816" rel="nofollow">http://forums.leaflabs.com/topic.php?id=103&page=2#post-816</a> IIRC the issues were: 1. Products like DS1307/DS3231 are accurately calibrated for time and temperature drift at the factory, 2. The calibration procedure described by ST in their application note for the RTC on the STM32F103's needed expensive equipment, or a long time. 3. The RTC on the STM32F103 only gives a seconds count, and is not a 'full calendar' like the Maxim products (the STM32F4 has a better RTC) 4. The ST application note on using the RTC on STM32 provided a 'constant time' mechanism to get the date and time (it woke up every second and calculated everything), but that seems less than ideal for low-power. Also if it were a low-priority interrupt, it may 'jitter' when it is used (gets blocked by higher priority interrupts). If it were high-priority, it might block events. 5. People hadn't found an Open Source way to convert seconds into date/time as it is needed, so it seemed hard to use unless by applying the ST app note (there are functions in newlib to help, so IMHO this was lack of knowledge, not a fundamental problem) 6. Maybe people hadn't found an Open Source way to set the RTC conveniently (e.g. to a reference date/time like 1st Jan 1970 midnight), given the date/time *NOW*. Without that timestamps are harder to compare nicely. (there are functions in newlib to help) bubulindo on "Maple Real-time clock implementation" http://forums.leaflabs.com/topic.php?id=1499#post-10060 Mon, 02 Apr 2012 02:39:03 +0000 bubulindo 10060@http://forums.leaflabs.com/ Meanwhile STM32F4 discovery came in the way, then work, then house painting and I haven't ran any conclusive test regarding the accuracy of the different clock sources. I have read that LSI is not that accurate, but found no info on HSE. :\ samtal on "Maple Real-time clock implementation" http://forums.leaflabs.com/topic.php?id=1499#post-10056 Mon, 02 Apr 2012 01:39:54 +0000 samtal 10056@http://forums.leaflabs.com/ Thanks. The STM32 RTC is a real one, having full power backup under sleep or standby modes, and need no external clock device (except a 32378 Hz crystal or line frequency). I can see no good reason to use external clock, but to be honest, I did not fully finished my implementation and have no experience yet with its use. I will try and post my conclusions. One thing I found out: The RTClock.h file somehow collides with the delay function, making it unrecognized. (see my post about it). samtal bubulindo on "Maple Real-time clock implementation" http://forums.leaflabs.com/topic.php?id=1499#post-9884 Sun, 25 Mar 2012 14:05:20 +0000 bubulindo 9884@http://forums.leaflabs.com/ Well, Accuracy when comparing between the external low frequency clock with the internal. Between the HSE and LSE clock, I guess the difference is the low power modes. The LSE clock remains active and clocking the RTC whilst the HSE can be stopped in low power modes. samtal on "Maple Real-time clock implementation" http://forums.leaflabs.com/topic.php?id=1499#post-9881 Sun, 25 Mar 2012 10:56:46 +0000 samtal 9881@http://forums.leaflabs.com/ Thanks bubulindo !! I was not aware of the files. I wonder why people still use external RTC for the Maple ??? Any idea? samtal bubulindo on "Maple Real-time clock implementation" http://forums.leaflabs.com/topic.php?id=1499#post-9880 Sun, 25 Mar 2012 05:28:02 +0000 bubulindo 9880@http://forums.leaflabs.com/ If you follow this post: <a href="http://forums.leaflabs.com/topic.php?id=1058" rel="nofollow">http://forums.leaflabs.com/topic.php?id=1058</a> You'll get to the github page (<a href="https://github.com/bubulindo/MapleRTC" rel="nofollow">https://github.com/bubulindo/MapleRTC</a>) of an RTC clock implementation that takes the external and internal crystals. You can either use the .c functions or the class. samtal on "Maple Real-time clock implementation" http://forums.leaflabs.com/topic.php?id=1499#post-9879 Sun, 25 Mar 2012 02:08:26 +0000 samtal 9879@http://forums.leaflabs.com/ Hi, The ST32F1XX has a full built-in RTC with all necessary registers and calibration features, as well as off-power operation. There are also nice ST application notes on how to implement such RTC. Yet, TTBOMK, Maple does not support that RTC, and no Maple rtc.h or rtc.c files exist. I have seen an old form discussion regarding the RTC, (<a href="http://forums.leaflabs.com/topic.php?id=1043#post-6370" rel="nofollow">http://forums.leaflabs.com/topic.php?id=1043#post-6370</a>) but to my surprise users suggest the use of external RTC, ignoring the built-in one. Has anyone successfully implemented the internal RTC and can help in implementing it? Thanks samtal