Multi-mode SCSI backplane and detection logic
View Patent ↗The present invention includes a multi-mode SCSI backplane and a detection logic that is used in conjunction with the backplane. In this invention, the SCSI backplane can be configured in different modes, included simplex mode and duplex mode. The detection logic can also detect when an illegal configuration is connected to the SCSI backplane and indicate the presence of the illegal configuration by triggering a light emitting diode (LED) or some other indicating mechanism. The detection logic is implemented with a handful of cost-effective field effect transistors (FETs), resistors and LEDs and no additional IC logic gates or Programmable Array Logic (PAL) is necessary.
1. A configuration logic circuit for a multi-mode SCSI backplane comprising:
first and second SCSI connectors coupled to the SCSI backplane;
a fault output coupled to the first SCSI connector;
a mode output coupled to the second SCSI connector; and
wherein the second SCSI connector comprises:
a first contact configured to open and close a first transistor, wherein the first transistor is connected to the mode output; and
a second contact configured to open and close a second transistor, wherein the second transistor is connected to the fault output.
2. The configuration logic circuit of claim 1 , wherein the first transistor selectively couples the second contact to the mode output.
3. The configuration logic circuit of claim 1 , wherein the second transistor selectively couples fault output to ground.
4. The configuration logic circuit of claim 1 , wherein said circuit comprises a fault indicator coupled to the fault output that indicates when an illegal configuration is coupled to the SCSI backplane.
5. The configuration logic circuit of claim 4 , wherein said fault indictor comprises a light emitting diode.
6. The configuration logic circuit of claim 1 , wherein said circuit comprises a mode indicator coupled to the mode output that indicates a configuration made for the SCSI backplane.
7. The configuration logic circuit of claim 6 , wherein said mode indicator comprises a light emitting diode.
8. The configuration logic circuit of claim 1 , wherein said circuit does not include any programmable array logic (PAL) circuitry.
9. A multi-mode SCSI backplane that includes configuration logic circuitry, said backplane comprising:
a SCSI connector that includes a first, second and third connector contact,
wherein the first connector contact is coupled to a first gate of a first transistor, and said first transistor is also coupled to a mode output and the second connector contact;
the second connector contact is coupled to a second gate of a second transistor, and said second transistor is also coupled to a fault output and a ground; and
the third connector contact is coupled to a third gate of a third transistor, and said third transistor is also coupled to the fault output.
10. The multi-mode SCSI backplane of claim 9 , wherein said SCSI backplane does not include programmable array logic (PAL) circuitry.
11. The multi-mode SCSI backplane of claim 9 , wherein said SCSI connector is a 68-contact SCSI connector that conforms with the SCSI Parallel Interface-2(SPI-2) connector contact configuration, and wherein said first connector contact has contact address number 52 , said second connector contact has contact address number 19 and said third connector contact has contact address number 20 .
12. The multi-mode SCSI backplane of claim 9 , wherein said first, second and third transistors are field effect transistors.
13. The multi-mode SCSI backplane of claim 9 , wherein said fault output is coupled to a light emitting diode that indicates when there is an illegal configuration on the SCSI backplane.
14. The multi-mode SCSI backplane of claim 9 , wherein said mode output is coupled to a light emitting diode that indicates a mode for the SCSI backplane.
15. The multi-mode SCSI backplane of claim 14 , wherein said mode is simplex mode or duplex mode.