Q & A – PLL IC (Clock Generator)

This document provides some frequently asked questions about Sandra. Please read the Help File as well!

Q: Does Sandra support the clock generator of my mainboard?
A:
The clock generator is supported only if the following are true:

  1. The mainboard is known, thus the PLL IC is known or PLL IC can be auto-detected.
  2. The mainboard SMBus/i2c controller is detected and enabled.
  3. The PLL IC is actually connected to the SMBus/i2c bus.
  4. The PLL IC supports read-back.
  5. The PLL IC is supported. See the Compatibility Document for the list of supported chips.

Q: PLL IC detection locks up my computer completly! Why and how do I fix it?
A:
Your PLL IC is write-only. See Chipset Q & A for more information.

Q: Why doesn’t Sandra detect PLL ICs natively?
A:
Only the very latest PLL IC chips can be autodetected. The older ones cannot – most cannot be detected at all!

Q: Sandra detects my PLL IC incorrectly!
A:
Go to module Options and turn Auto Detect PLL IC off. If this does not help, contact us.

Q: Why does Sandra support so few clock generators?
A:
The reasons are quite a few:

  • Only modern clock generators (since around 1997) are software programmable.
  • Most clock generators are write-only (e.g. the entire IC-Works line). This means that the bus speed can be changed but it cannot be detected. This is not a problem for programs like SoftFSB but it is critical for Sandra.

Q: Sandra does not detect the PLL IC of my mainboard!
A:
PLL ICs (unlike other SMBus/i2c devices) cannot be detected. This is because there are no ID registers and most are write-only. One of the few possible ways is to do it by mainboard type. If Sandra does not know what your board uses, have a look and let us know.

Q: Sandra does detect the PLL IC type but cannot find it.
A:
There are various reasons why this can happen:

  • Sandra does not detect the SMBus/i2c controller or the controller has locked.
  • The PLL IC is not at its known address or it is write-only.
  • The PLL IC has locked.

Q: Sandra does detect the PLL IC and reads it fine, but I get no useful information.
A:
If the speed selected is by hardware then no useful information can be inferred. Only if the chip is software programmed useful information can be read back.

Q: How can I modify the FSB by software?
A:
Sandra is an analyser not a PLL IC programmer. You can use programs like SoftFSB to program the PLL IC.

 

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