Hi,
Can you give me a concrete example of an application requiring the cortex-R family (exept for the watch and the video-recording). Given the gap in price between processors, Except in the case of a large-scale purchase why not choose the cortex-A family ?
regards,
Hello Jerome.
R stands for the Realtime.
Coretx-R is intended to be used in Realtime embedded area.
The key functions are TCM and no MMU.
The cahces and MMU would not guarantee a definite execution time because of the replace (i.e. refill).
If the definite execution time was needed, programs could be executed on TCM.
On the other hands, A stans for Applicaition.
Cortex-A would widely utilize caches and MMU in the High performance area.
Of course, the definite execution time would not be guaranteed.
Best regards,
Yasuhiko Koumoto.
Hi yasuhikokoumoto,That it ! i'm searching the good way to explains it !
To summarize this simply without going into too many technical details :
The CortexR is specialy make for instant precision treatments that do not require a large constant information flow as often asks embedded objects.
Thanks
I am looking for examples of using to accompany
Another example is in radio.
Mobile phone data, Bluetooth, Wi-Fi have ARM Cortex-R processors in them. So in your smartphone, chances are that you have it
A small precision for novices reading, real-time does not necessarily mean it needs to be done NOW (like realtime Mpeg encoding), but it means you know when and how long it will take to execute. It must be predictable.
Alban
Thank you for these precisions and these examples Alban
Hi Jerome,
sorry for the late reply (I've been on holiday). Regarding specific application examples, one of the challenges of finding deployments of Cortex-R cores is that they are often deeply embedded into designs, sometimes along Cortex-A cores too, and not all partners want to highlight that they are using our cores. As others in the thread have highlighted, they come into their own where hard real-time performance is required, and a great example of this is disk drives:
http://www.arm.com/markets/embedded/hdd-ssd.php
Both SSD and HDD use Cortex-R (although we are seeing both -M and -A families being used in some devices too now).
They are also widely used in LTE modems in mobile phones:
Five things you may not know about Cortex-R Series processors
ARM Cortex-R real-time processors speed your mobile communications
As others have listed above, the main difference between A and R families is the addition of TCMs, and the change from MMU to MPU. However the Cortex-R family also has other features to help with real-time applications such as low-latency peripheral ports (designed to allow fast access to peripherals without transactions getting held up by other bus traffic), and interruptable Load-Store multiples (if an interrupt arrives during an LDM/STM operation to normal memory, the transaction can be abandoned to take the interrupt. It is then repeated after the interrupt handler completes).
Jon
It is a good use of the Cortex -R. Thanks for this very telling example !
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