Arm Community
Site
Search
User
Site
Search
User
Groups
Arm Research
DesignStart
Education Hub
Graphics and Gaming
High Performance Computing
Innovation
Multimedia
Open Source Software and Platforms
Physical
Processors
Security
System
Software Tools
TrustZone for Armv8-M
中文社区
Blog
Announcements
Artificial Intelligence
Automotive
Healthcare
HPC
Infrastructure
Innovation
Internet of Things
Machine Learning
Mobile
Smart Homes
Wearables
Forums
All developer forums
IP Product forums
Tool & Software forums
Support
Open a support case
Documentation
Downloads
Training
Arm Approved program
Arm Design Reviews
Community Help
More
Cancel
Developer Community
IP Products
Processors
Jump...
Cancel
Processors
Classic processors forum
help needed on arm7 timer interrupt
Blogs
Forums
Videos & Files
Help
Jump...
Cancel
New
State
Accepted Answer
+1
person also asked this
people also asked this
Replies
5 replies
Subscribers
2 subscribers
Views
3649 views
Users
0 members are here
Arm7
Related
help needed on arm7 timer interrupt
Offline
duoduo duoduo
over 7 years ago
Note: This was originally posted on 15th January 2009 at
http://forums.arm.com
Dear all !
i am trying to use a timer interrupt to call a function in an ARM7 platform.i hope this timer interrupt can happen in a 320 microseconds interval.however,i found that when i make the interval less than 11 milliseconds exception happened.
11 milliseconds is too slow for me.why this happened?can somebody help?many thanks!
additional:i made a big mistake in my description, mixing up microseconds with milliseconds. really sorry.
Top replies
Offline
Jacob Bramley
over 7 years ago
+1
verified
Note: This was originally posted on 15th January 2009 at http://forums.arm.com I'm not sure, but I think you may have mixed up your units somewhere along the line. 11 microseconds is considerably smaller...
0
Offline
duoduo duoduo
over 7 years ago
Note: This was originally posted on 16th January 2009 at
http://forums.arm.com
thanks a lot jacob
i check my codes and it seemed as if the timer interrupt could not my "non-interrupt code would never run".
your words made me firmly believe that my needed 320 microseconds is not too fast for an ARM7 chip.thank you again.
Cancel
Up
0
Down
Reply
Accept answer
Cancel
0
Offline
duoduo duoduo
over 7 years ago
Note: This was originally posted on 16th January 2009 at
http://forums.arm.com
i debug step by step and found where exception happened:when i used 320 microseconds and the routine came to the end of a function, i.e. the statement "return SUCCESS", it stopped there, after a while Undefined instruction exception happened.
and when i used 11 milliseconds ,it ran well.
why?can anybody help?
Cancel
Up
0
Down
Reply
Accept answer
Cancel
0
Offline
Felix Varghese
over 7 years ago
Note: This was originally posted on 28th January 2009 at
http://forums.arm.com
In many controllers, the timer keeps running even if you stop at a breakpoint.. so you cant really debug timers using single stepping.. you could probly check if that is the case here.. can you tell us the name of the controller you are using?
Cancel
Up
0
Down
Reply
Accept answer
Cancel
0
Offline
duoduo duoduo
over 7 years ago
Note: This was originally posted on 3rd February 2009 at
http://forums.arm.com
arm7
s3c44b0
Cancel
Up
0
Down
Reply
Accept answer
Cancel
+1
Offline
Jacob Bramley
over 7 years ago
Note: This was originally posted on 15th January 2009 at
http://forums.arm.com
I'm not sure, but I think you may have mixed up your units somewhere along the line. 11 microseconds is considerably smaller than 320 milliseconds
Setting the timer interval to a value that is too small will not itself cause an exception (other than the interrupt itself). Usually, this would cause a timer event to occur before the previous event had completed, which would result in the interrupt handler appearing to run in a continuous loop; your non-interrupt code would never run. There are situations and configurations which could result in an exception, but I don't think you are seeing this.
For reference:
The typical ARM7 microcontroller clocks at about 60MHz. One cycle at this frequency is about 17 nanoseconds, so your 11 microseconds threshold is about 647 cycles. It is quite possible for an interrupt routine to take that long, so it's likely that you're seeing the infinite interrupt loop that I described. However, 320 milliseconds is much longer than that so you have plenty of head room :-)
I hope that helps,
Jacob
Cancel
Up
+1
Down
Reply
Reject answer
Cancel
More questions in this forum
By title
By date
By reply count
By view count
By most asked
By votes
By quality
Descending
Ascending
All recent questions
Unread questions
Questions you've participated in
Questions you've asked
Unanswered questions
Answered questions
Questions with suggested answers
Questions with no replies
Answered
How to use CoreSight debug and trace ?
+1
Arm Development Studio
CoreSight Debug and Trace
Arm9
4498
views
1
reply
Latest
over 3 years ago
by
Matt Sealey
Answered
PWM code not running on LPC2129 board but working on logic analyzer .
+1
Arm7TDMI-S
4027
views
1
reply
Latest
over 3 years ago
by
karthik dharma
Answered
Problem in calling the function in ISR
+2
Arm7tdmi
9311
views
8
replies
Latest
over 3 years ago
by
42Bastian Schick
Answered
Delay Subroutine LPC2148 Assembly
+1
Arm7
GPIO
Arm Assembly Language (ASM)
7877
views
3
replies
Latest
over 4 years ago
by
Yasuhiko Koumoto
Answered
armv5TE
+1
Armv5T
Armv5TE
Armv5
5285
views
3
replies
Latest
over 4 years ago
by
kalle
<
>
View all questions in Classic processors forum