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:
- The mainboard is known, thus the PLL IC is known or PLL IC can be auto-detected.
- The mainboard SMBus/i2c controller is detected and enabled.
- The PLL IC is actually connected to the SMBus/i2c bus.
- The PLL IC supports read-back.
- 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.