My Sam460ex@1150 MHz is reported running in 1265 MHz when booting MorphOS 3.17.

showconfig reports:
PROCESSOR: 460EX (G3) (V10.4) 1265MHz (FSB 1265MHz)

The correct speed is 1150 MHz and the FSB speed is 50 MHz (as reported by U-BOOT 2015a).

1150 / 50 = 23.

Sam460 comes with three different FSB speeds: 50, 55 and 60. It seems MorphOS takes for granted my Sam460 has a 55 MHz FSB. 23 x 55 = 1265 MHz.

What is needed for MorphOS to detect the correct FSB speed for a certain Sam460 board?

Seems to be hardcoding, you may report this bug.

> My Sam460ex@1150 MHz is reported running in 1265 MHz

Seems nothing changed since your old thread.

Quote:

I knew I hade mentioned it somewhere, but couldn't find it. Thanks. That thread points to another thread that mentions 50 and 55 MHz, but not 60 MHz.

Known CPU frequencies after some googling:

Sam460ex Lite: 1017.5 MHz (guessing 55 MHz FSB with a 18.5x multiplier, can anyone confirm?) https://forum.amiga.org/index.php?topic=57789.msg639100#msg639100

Sam460cr/le: 1.1 GHz (50 or 55 MHz FSB, or just 1115 MHz rounded to 1.1 GHz?)

Sam460ex: 1115 MHz (50 MHz FSB, 22.3x multiplier) https://morph.zone/modules/newbb_plus/viewtopic.php?forum=11&topic_id=11840&post_id=129190&viewmode=flat&sortorder=0&showonepost=1

Sam460ex: 1150 MHz (50 MHz FSB, 23x multiplier) - the first revision. I have one.

Sam460ex: 1166 MHz (Maximum speed, perhaps never sold at this clock rate) http://www.sam4x0.com/sam460ex.html

Would be interesting to hear from someone with a board running FSB at 60 MHz.

And what exactly is FSB in Sam460ex/lite/cr/le?

FSB (front-side bus) was originally meant for CPU - Northbridge bus.

AMCC460ex is SoC with integrated memory controller - so traditional "FSB" is inside CPU.
460ex have four internal buses according to datasheet:
-Processor Local Bus (PLB), 128bit, 133-200 MHz - from this clock is derived CPU core and memory clocks. Also DDR, PCIe and PCI are connected there via High Bandwith segment. This bus is nearest to traditional FSB definition.

-On-chip Peripheral Bus (OPB), 32bit address, 32bit data, 66-100MHz

-Advanced High-performance Bus (AHB), 32bit address, 32bit data, 66-200MHz, synchronized with PLB - USB and single SATA (Sam460ex) is connected

-Device Control Register bus (DCR), 32bit data, 10bit addr

So again, what is FSB frequency in this CPU context?
The nearest frequeny to U-boot reported FSB clock ( 50MHz ) is SysClk input, which should have nominally 66-100 MHz.

Maybe is better to ask directly A-Cube what does FSB means here.


[ Edited by sailor 01.01.2023 - 19:26 ]

True, FSB is the wrong word (taken from the PC world). The closest is, like you say, PLB frequency. 287 MHz in my case.


[ Edited by duga 02.01.2023 - 21:50 ]

> The nearest frequeny to U-boot reported FSB clock ( 50MHz ) is SysClk input

Yes, I'd say that's what's clocked at 50, 55 or 60 MHz in the Sam460. It's been called 'reference clock' by a MorphOS team member, so it should be the RefClk, SysClk or similar.

Quote:

It perhaps would be better if the CPU speed in MorphOS were taken from freqPLB, DDR freq or cpu_clk/freqProcessor instead.

My Sam460ex (with a 50 MHz "CLK freq"):
PLB 287,5 * 4 = 1150 MHz CPU speed
PLB 287,5 * 2 = 575 MHz DDR2 speed

For a 1066 MHz machine I assume:
PLB 266,5 * 4 = 1066 MHz CPU speed
PLB 266,5 * 2 = 533 MHz DDR2 speed

Quote:

Time flies, I didn't even remember that this issue has been discussed around 6 years ago already ...
Fact is though that the MorphOS initial setup seems to assume a reference clock of 55MHz up to the current date and typically is off around 10% +/- for anything that uses 50 or 60MHz reference clocks.
AFAIR, there was no proper way to figure out/read back the actual reference clock unless you measure it against some other independently clocked unit on the board. As there was only limited interest in Sam460 MorphOS support and we couldn't really figure out how many Sam460 were affected, we left the code as-is ever since.

@cyfm

If it's of any help, this is what Ranger under AmigaOS 4.1 shows:

CPU Speed: 1150 MHz
Fron Side Bus Speed: 287 MHz
Time Based Speed: 1150 MHz
Frequencies: VBlank: 50 PSupply: 50 EClock: 1150000011 Hz (1150.000011 MHz)

> Sam460cr/le: 1.1 GHz (50 or 55 MHz FSB, or just 1115 MHz rounded to 1.1 GHz?)

According to the recent press release and product page, "the Sam460LE of this production run is now running at 1.14 Ghz instead of 1.10 Ghz".