This tool plugs
into
one connector of a carrier board that uses the ETX SBC (Small Board
Computer) as its heart. See the Ultrasound
Control Card elsewhere in
the gallery for an example of such a card. The LEDs on this board
can help pinpoint connection or component faults on the carrier board.
Gory details (for the geeks among you...): Many ETX boards use programmable large-scale logic devices such as FPGAs (Field Programmable Gate Array) to connect the popular PCI bus to their system. However, the PCI bus has about fifty signals, none of which are disposable. When a card is exhibiting a PCI problem, it can be difficult with software to determine the exact cause. To use this tool, one temporarily programs the logic device on the carrier board to accept a slow clock signal from an oscillator on the tool and sequentially drive each LED pair low (lights the green LED in the pair), then high (lights the red LED in the pair), then disconnect from the LED. When disconnected, both LEDs of the pair glow very dimly.
If a connection from the logic device to the PCI connector is broken, then that LED pair will simply stay dimly lit. The failure of the pair to drive bright green then bright red will be quite noticeable as the test will appear to skip that LED pair. Similarly, if a wire is stuck low, the green LED of the pair will be on all the time. If stuck high, the red LED will be on constantly. If a short exists between two signals of the PCI bus, then two pairs of LEDs will be driven when either signal comprising the short is tested.
When an LED pair misbehaves, the user reads the adjacent text naming the signal and refers to their schematic of the carrier board to track down the fault directly.
This board is a "simple" level project.
Gory details (for the geeks among you...): Many ETX boards use programmable large-scale logic devices such as FPGAs (Field Programmable Gate Array) to connect the popular PCI bus to their system. However, the PCI bus has about fifty signals, none of which are disposable. When a card is exhibiting a PCI problem, it can be difficult with software to determine the exact cause. To use this tool, one temporarily programs the logic device on the carrier board to accept a slow clock signal from an oscillator on the tool and sequentially drive each LED pair low (lights the green LED in the pair), then high (lights the red LED in the pair), then disconnect from the LED. When disconnected, both LEDs of the pair glow very dimly.
If a connection from the logic device to the PCI connector is broken, then that LED pair will simply stay dimly lit. The failure of the pair to drive bright green then bright red will be quite noticeable as the test will appear to skip that LED pair. Similarly, if a wire is stuck low, the green LED of the pair will be on all the time. If stuck high, the red LED will be on constantly. If a short exists between two signals of the PCI bus, then two pairs of LEDs will be driven when either signal comprising the short is tested.
When an LED pair misbehaves, the user reads the adjacent text naming the signal and refers to their schematic of the carrier board to track down the fault directly.
This board is a "simple" level project.