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The AmigaOne - Other Considerations

THIS IS STILL A WORK IN PROGRESS - SUGGESTIONS WELCOME ThOUGH!


Since the AmigaOne was released a number of issues have arisen which need to be considered:

Problem recognising USB devices
When USB devices are connected and then disconnected, the hardware does not recognise when another device is connected. This is due to a fault at manufacture on some machines, where instead of a resistor being fitted to dissipate the voltage, a capacitor was fitted which retains the voltage so the new device is not recognised. This is a relatively simple fix to the motherboard if you have the skills and tools to swap the components, otherwise we recommend that you buy a powered USB hub and let that take care of the problem instead. Unpowered hubs are not suitable.

File corruption using DMA with VIA 686 IDE controller
Very soon after the AmigaOne was released to developers, they found that running with DMA on drives caused data corruption and the recommendation was to run in PIO mode only, at a maximum speed of 16MB/s rather than 100MB/s or 133MB/s which the drives should be capable of. This was traced to a lack of understanding as to how the onboard VIA chip processed I/O but it appeared that VIA did not want to supply any answers. While it was not a problem for AmigaOS 4.0, Linux users accessing IDE drives connected to the onboard VIA IDE controller must specify 'ide=nodma' on the bootargs parameter passed at startup.

Currently there are two solutions to this problem:

  1. Patch the Motherboard - some people have opted to have their motherboard "fixed" (the exact fix has not been made public) and this seems to solve the problem, but problems have been reported running the 2.4.26 kernel for Debian Linux since. It seems a later kernel may be the solution.

  2. Bypass the onboard VIA chip - many people have opted to use an add-on IDE card for Ultra-ATA and ATAPI drives, such as the SiL0680 based PATA cards or various SiL SATA cards, bypassing the onboard VIA chip completely. See Peripherals for more information on these.

Problem with blank screen when booting into AmigaOS 4.0
Some users have had a problem when booting into AmigaOS 4.0 in that once kickstart has loaded and the reset is issued, it displays a blank screen instead of the Workbench screen.
Possible causes:

  • Primary/Slave settings on hard drives don't match their usage
  • Incompatible CDROM drive,

Problem installing Debian Woody with Radeon 7500
Linux not installing correctly when Radeon 7500 setting specified for video card - used fbdev instead.

Unstable systems
The following apsects have caused stability issues in the AmigaOne:

  • incompatible memory stick.
    symptom : whatever random behaviour.
    solution : change the memory stick to one supplied by an approved A1 dealer.
    Kingston buffered sticks seem to be a common working model (preferably Registered ECC).
  • use of two memory sticks
    symptom : whatever random behaviour.
    solution : remove all but the 1st.
  • wrong VCORE (see item below)
  • bad IDE cabling
    (see si680ide releasenotes, URL above)
  • insufficient CPU cooling
    (see cooling URL Labove)
  • hard drive errors
    cause : trying to use an UDMA mode that a drive claims to support but which it does not really.
    solution : try the mode just below it.
  • motherboard battery worn out (the CR2032).
    symptom : random behaviour as early as in UBoot
    solution : change the battery
    (they cost NZ$5.88 from DSE, NZ$3.99 from The Warehouse and NZ$3.65 from Foodtown).

Incorrect VCORE
It appears that some A1's may be running with a wrong VCORE (the CPU core's supply voltage). VCORE has nothing to do with overclocking - it should be set as close as possible (but always below, never above) to nominal value as per Motorola / FreeScale specifications for the exact processor model as written on the silicon die. The ONLY way to make sure what processor model you have is to remove the heatsink and fan, and look at what is written on the CPU silicon die. Every letter and digit matters.

Given that there is an exponential relationship between VCORE and heat, you have to make sure that you have adequate cooling before changing anything, as raising VCORE up to nominal without adequate cooling can FRY your CPU - ask Helgis?

The VCORE can be changed by setting the 4 dip switches next to the ATX Power Supply connector on the motherboard, and the JP17 jumper close to this dipswitch pad. Nothing is to change on the CPU daughterboard.

The table below, taken from the MAI Articia S Teron CX Evaluation Board User's manual, defines the VCORE from the setting of the 4 dipswitches and the JP17 jumper :

1 2 3 4 JP17 VCC_CORE
Off Off Off Off Short 1.34
On Off Off Off Short 1.39
Off On Off Off Short 1.44
On On Off Off Short 1.49
Off Off On Off Short 1.54
On Off On Off Short 1.59
Off On On Off Short 1.64
On On On Off Short 1.69
Off Off Off On Short 1.74
On Off Off On Short 1.79
Off On Off On Short 1.84
On On Off On Short 1.89
Off Off On On Short 1.94
On Off On On Short 1.99
Off On On On Short 2.04
On On On On Short 2.09
 
1 2 3 4 JP17 VCC_CORE
Off Off Off Off Open 1.244
On Off Off Off Open 2.14
Off On Off Off Open 2.24
On On Off Off Open 2.34
Off Off On Off Open 2.44
On Off On Off Open 2.54
Off On On Off Open 2.64
On On On Off Open 2.74
Off Off Off On Open 2.84
On Off Off On Open 2.94
Off On Off On Open 3.04
On On Off On Open 3.14
Off Off On On Open 3.24
On Off On On Open 3.34
Off On On On Open 3.44
On On On On Open 3.54

As a general rule of thumb use these VCORE values:

  • PPC 750 FX (G3) - VCORE of 1.44V (1-off 2-on 3-off 4-off JP17-short)
  • PPC 7451 (G4) - VCORE of 1.59V (1-on 2-off 3-on 4-off JP17-short)

Disclaimer: Amiga Auckland have prepared the above information for the use of its members based on our experiences and as such is subject to revision at any time. Amiga Auckland cannot guarantee any of the information and cannot be held accountable for any issues that may result from using it.


Copyright 2005 Amiga Auckland Inc. All rights reserved.
Revised: December 05, 2005.