A Comparison of ARM Cortex-A Series Processor Performance Classifications

Re:A Comparison of ARM Cortex-A Series Processor Performance... by dragontamer on Thursday September 28, 2023 @01:18PM (#37692720)

> Finally, anyone who tries to tell me that A53 is "high-end" in 2023 will get some side-eye.

You know that Microchip's SAM9x60 from 2020 is running ARM926EJ-S (aka: ARMv5) with J for Jazelle instructions, right?

"Embedded" world moves slower than consumer world. ARM Cortex-A53 is high-end for embedded. This is a world where 8051 and Z80 chips are still being made.

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I feel like a lot of MPUs released in the last 2 years (i.MX from NXP, STM32MP1 and soon-to-be-released MP2, etc. etc.) are in the ARM-Cortex A7-ish tier.

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Re:A Comparison of ARM Cortex-A Series Processor Performance... by RicoElectrico on Thursday September 28, 2023 @01:24PM (#37692797)

Any advantage to use ARMv5 at this point? Knowing that ARM designs a whole spectrum of processors over performance/power/area triangle, has there really been no alternative?

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Re:A Comparison of ARM Cortex-A Series Processor Performance... by dragontamer on Thursday September 28, 2023 @01:30PM (#37692862)

Its an eye-raising decision for sure, but this is literally Microchip's most recent MPU design. Microchip has Cortex-A5 and Cortex-A7 chips available for those who want them. But the most recently released chip is in fact SAM9X60.

My assumption is that Microchip has a large customer who is demanding as perfect of a match to some 20+ year old design, and Microchip is more than happy to produce this ancient design for them.

ARM926EJ-S gives us a big hint: J for Jazelle. If some customer has some old Embedded Jazelle/Java code that they haven't bothered to update in the last 20 years, perhaps its easier for Microchip to just keep making ARM926EJ-S rather than forcing them to upgrade to Cortex-A5 or A7 (which although newer... these newer chips have all gotten rid of Jazelle / hardware execution of Java code).

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Code-wise, there's probably a lot of downsides. But electrically speaking, the SAM9X60 is an extremely well designed BGA with well-matched VCC/GND pins that has a 4-layer reference design. (Or at least: the SiP version SAM9X60-D1G)

Designing an 14mm x 14mm BGA223 that can be routed on a 4-layer board is no small feat. And therefore, this is probably one of the easiest BGAs to layout for a beginner, and lowers your PCB production costs.

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