RTC !
Hi,
When i compiled the following program , (taken from /usr/src/linux/Documentation/rtc.txt )
(See attached file: rtc2.c)
it gave me the following error:
[root@msatuts1 timer1]# gcc -s -Wall -Wstrict-prototypes rtc2.c -o rtc2 In file included from rtc2.c:17:/usr/include/linux/mc146818rtc.h:29: parse error before `rtc_lock' /usr/include/linux/mc146818rtc.h:29: warning: data definition has no type or storage class
rtc2.c:25: warning: return type of main' is not int' [root@msatuts1 timer1]#
Is this a bug?Can anyone tell me how to remove this parse error ?
With Regards,
--Niraj
---------------------- Forwarded by Niraj Punmia/HSS on 04/20/2001 04:31 PM
---------------------------
Niraj Punmia
04/12/2001 02:50 PM
To: [email protected]
cc:
Subject: RTC !!
Hi ,
The RTC interrupt is programmable from 2 Hz to 8192 Hz, in powers of 2. So the interrupts that you
could get are one of the following: 0.122ms, .244ms, .488ms, .977ms,
1.953ms, 3.906ms, 7.813ms, and so on. Is there any workaround , so that i
can use RTC
for meeting my requirement of an interrupt every 1.666..ms!! ( I know that i can use UTIME or #define HZ 600, but i want to know if i can use RTC for this purpose )
With Regards,
--Niraj
---------------------- Forwarded by Niraj Punmia/HSS on 04/12/2001 02:33 PM
---------------------------
James Stevenson <[email protected]> on 04/09/2001 06:42:44 PM
Please respond to [email protected]
To: Niraj Punmia/HSS@HSS
cc:
Subject: Re: 1.6666.... ms interrupts needed!!
Hi
instead of modifing the time irq freq you could try using the realt time clock (rtc) it will generate irqs with better timing and you also wont hit system performance as much by modifing the timer ever time the timer send an irq some code is run to see it schedule need to be called the more times schedule is called a second the worse the system performance is because of the task switching overhead.
Quoted 5 lines · you
Hi.
Quoted 8 lines
We are simulating air interface of GPRS on LAN. A TDMA(time division multiple access) frame duration is 40ms. Each TDMA frame consists of 24 timeslots. Each timeslot is of 40/24 ms (i.e 1.66666.......ms) . To know what current
timeslot it is, we need a timer interrupt after every 1.6666... ms . Since we
are implementing this on LAN, minor jitters once in a while can be tolerated (say 0.2 ms more or less once a while would be OK).
As of now, we are modifying the HZ value inparam.hto 600. This gives us
a CPU tick of 1.6666.... ms. (i.e 1/600sec). I want to know if it would
affect
Quoted 2 lines
the perfomance of the CPU.
Is there a better way to achieve the granularity of 1.666...ms . Would
the
Quoted 8 lines
UTIME patch be a better way from performance or any other point of view than this method?
With Regards,
Niraj Punmia
Quoted 6 lines
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Quoted 17 lines · [email protected] wrote:
Hi,
When i compiled the following program , (taken from
/usr/src/linux/Documentation/rtc.txt)(See attached file:
rtc2.c)it gave me the following error:
[root@msatuts1 timer1]# gcc -s -Wall -Wstrict-prototypes
rtc2.c-o rtc2 In file included from rtc2.c:17:/usr/include/linux/mc146818rtc.h:29: parse error before `rtc_lock'/usr/include/linux/mc146818rtc.h:29: warning: data definition has no type or storage class
rtc2.c:25: warning: return type ofmain' is notint' [root@msatuts1 timer1]#
Quoted 1 line
Is this a bug?Can anyone tell me how to remove this parse error ?
It works fine for me using a 2.2.16 kernel and egcs-2.91.66 (see below)...
bash-2.04$ gcc -s -Wall -Wstrict-prototypes rtc2.c -o rtc2 rtc2.c:24: warning: return type of main' is not int' bash-2.04$ ./rtc2
RTC Driver Test Example.
Counting 5 update (1/sec) interrupts from reading /dev/rtc: 1 2 3 4 5 Again, from using select(2) on /dev/rtc: 1 2 3 4 5
Current RTC date/time is 20-4-2001, 12:34:01.
Alarm time now set to 12:34:06.
Waiting 5 seconds for alarm... okay. Alarm rang.
Periodic IRQ rate was 1024Hz.
Counting 20 interrupts at:
2Hz: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 4Hz: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 8Hz: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 16Hz: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 32Hz: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 64Hz: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
*** Test complete ***
Typing "cat /proc/interrupts" will show 131 more events on IRQ 8.
bash-2.04$
Regards,
Jesper Juhl
[email protected]