[RTOS Support] Runtime stats with 16bit timer

The FreeRTOS kernel is now an MIT licensed AWS open source project, and these pages are being updated accordingly.

Quality RTOS & Embedded Software

About Contact Support FAQ Download

Menu

Quick Start

Supported MCUs

PDF Books

Trace Tools

Ecosystem

Quick Start Guide

Support Forum

⇓ Download Source ⇓

FreeRTOS+ Ecosystem

FreeRTOS+TCP:
Thread safe TCP/IP stack

SafeRTOS:
TUV certified RTOS

OpenRTOS:
Commercial Licensed RTOS

Fail Safe File System:
Ensures data integrity

FreeRTOS BSPs:
3rd party driver packages

Trace & Visualisation:
Tracealyzer for FreeRTOS

CLI:
Command line interface

WolfSSL SSL / TLS:
Networking security protocols

RTOS Training:
Delivered online or on-site

IO:
read(), write(), ioctl() interface

FreeRTOS+ Lab Projects

FreeRTOS+POSIX:
POSIX threading API

FreeRTOS+FAT:
Thread aware file system

FreeRTOS Support Archive

The FreeRTOS support forum is used to obtain active support directly from Real Time Engineers Ltd. In return for using our top quality software and services for free, we request you play fair and do your bit to help others too! Sign up to receive notifications of new support topics then help where you can.

This is a read only archive of threads posted to the FreeRTOS support forum. The archive is updated every week, so will not always contain the very latest posts. Use these archive pages to search previous posts. Use the Live FreeRTOS Forum link to reply to a post, or start a new support thread.

[FreeRTOS Home] [Live FreeRTOS Forum] [FAQ] [Archive Top] [March 2011 Threads]

Runtime stats with 16bit timer

Posted by Alex P. on March 13, 2011

Hello all,

I'm currently running FreeRTOS on a STM32. I'm having a problem regarding the run time stats. The timers on this micro controller are all 16 bit and this is causing the run time results to be completely wrong.

Is there an option to specify that the timer is coded in 16bits?

Thanks,
Alex

RE: Runtime stats with 16bit timer

Posted by Richard on March 13, 2011

Yes - the most common way is to configure the 16 bit timer to generate an interrupt each time it overflows (or reaches its maximum count if an overflow interrupt is not available), then have the interrupt handler simply count the number of overflows.

You than have two 16 bit numbers, one is the current timer counter value, and the other the number of overflows. You can generate a 32 bit number from the two by having the count of overflows being the two highest bytes in the 32 bit number, and the current counter value as the two lowest bytes. This also has a really low interrupt processing overhead.

Actual code examples are provided in both the PIC32 and RX600 editions of the FreeRTOS tutorial book.

Regards.