Re: [ts-7000] RTC registers

["Don W. Carr" <>]

Again, use hwclock to both set and read the RTC. Do NOT mess around with registers, as that code is not portable. The date system call, ONLY changes the time in memory, and does NOT synchronize it with the RTC, on reboot, you revert back to the previous time.

Also, please search for previous threads on this. Go to:

http://tech.groups.yahoo.com/group/ts-7000/

There is an excellent search feature for looking up old threads.

Don.

On 5/21/07, Kevin Cozens <> wrote:

Julien wrote:
> I'm trying to control date&hours with one of my program. To do this,
> I would like to use my TS5620. I read some details in TS7200 manual,
> about addresses of RTC registers (starting at 0x11700000), and about
> the size (just the first 14 bytes).
>
> Unfortunatly, I don't really understand how it works, since I read
> same value from 0x11700000 to 0x1170000E. For example if I write 0xF
> at 0x1170000E, I will read 0xF at 0x11700002 too.

The application I'm working on also needs to set date and time. It is probably
better to use the 'date' command but it is possible to set the date and time
by writing to the clock chip registers. I've done this sort of thing in the past.

Based on my past experience with RTC's, the 14 bytes that hold the date/time
information are not simple memory locations you can read or write to whenever
you want. There is a status register with a busy bit you need to check which
tells you when it is safe to write/read the registers.

The TS-7250 uses a DS-1687 RTC. If your board uses the same RTC package, you
can find the datasheet for it at:
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2757

Take a look at page 12 which has the details of three control register at
address 0Ah. In particular, look at the UIP (update-in-progress) bit. The
safest way to read/write to the chips is to wait until you see the UIP bit
transition from 1 to 0 before doing any reads/writes as that will guarantee
you at least 244uS of time for your operations.

It is also interesting to note in the datasheet that the RTC comes with 242
bytes of RAM. This is 128 bytes more than is available in the Motorola 6818
series of clock chips. Despite this, the TS-7250 information I've been reading
only talks about only 114 bytes of RAM as being available in the RTC.

--
Cheers!

Kevin.

http://www.ve3syb.ca/ |"What are we going to do today, Borg?"
Owner of Elecraft K2 #2172 |"Same thing we always do, Pinkutus:
| Try to assimilate the world!"
#include <disclaimer/favourite> | -Pinkutus & the Borg

-- 
Dr. Don W. Carr
J. G. Montenegro 2258
Guadalajara, Mexico
+52-333-630-0704
+52-333-836-4500 ext 2930

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