//===
- PCI-X可能可以向下相容33MHz PCI32的界面卡 ...
PCI-X是3.3V的,早期的33MHz/PCI32的卡需要5V - PCI-E跟PCI-X/PCI是不相容的？？？
- PCI的插槽長度約 8.5 cm
- PCI-X的插槽長度最長
- 將PCI 64-bit 介面卡安裝到 PCI 32-bit 的插槽內 還能正常運作
- 反之未必？
- 32-Bit/66MHz PCI 2.2 介面卡 可工作於66MHz或33MHz,
- 支援66MHz其電壓必定要工作在3.3V.
- 新的PCI 64bit 一般支援3.3V
- "插不進去別硬插就是"
//=== 傳統的PCI
"...
* PCI 1.0, which was merely a component-level specification, was released on June 22, 1992.
* PCI 2.0, which was the first to establish standards for the connector and motherboard slot, was released on April 30, 1993.
* PCI 2.1, released on June 1, 1995, allows for 66 MHz signaling at 3.3 volt signal voltage (peak transfer rate of 533MB/s), but at 33 MHz both 5 volt and 3.3 volt signal voltages are still allowed. It also added transaction latency limits to the specification.
* PCI 2.2 Power rails to provide 3.3 volt supply voltage are now mandatory.
* PCI 2.3 permits use of 3.3 volt and universal keying, but does not allow 5 volt keyed add in cards.
# PCI 3.0 is the final official standard of the bus, completely removing 5-volt capability.
# Mini PCI is a form factor of PCI 2.2 for use mainly inside laptops
# CardBus is a PC card form factor for 32-bit, 33 MHz PCI
# CompactPCI uses Eurocard-sized modules plugged into a PCI backplane.
# PC/104-Plus is an industrial bus that uses the PCI signal lines with different connectors.
..."
//=== nVidia nforce3
"... Integrates a fast PCI-to-PCI bridge running at 33 MHz. It includes an arbiter that supports six external master PCI slots. Features of the PCI interface include:
- PCI 2.3-compliant, 5 V tolerant???
- Supports six external PCI slots at 33 MHz
- Supports six bus master arbitration
- PCI master and slave interfaces
- Supports both master-initiated and slave-initiated terminations
- Bidirectional write posting support for concurrency
- Flexible routing of all four PCI interrupts
- Supports read ahead: memory read line (MRL) and memory read multiple (MRM)
[ref]
http://en.wikipedia.org/wiki/Conventional_PCI#Card_keying
http://www.nvidia.com/page/pg_20030918437537.html
http://www.pczone.com.tw/vbb3/thread/14/125494/
http://www.pcgamma.com/showthread.php?t=5274
http://blog.sina.com.tw/kio_orz/article.php?pbgid=30830&entryid=596632
http://en.wikipedia.org/wiki/File:PCI_Keying.png
