| ??? 03/21/07 09:28 Read: times Msg Score: +1 +1 Informative |
#135479 - Long Distance I2C Responding to: ???'s previous message |
You may be interested to know that modern computer displays like VGA monitors and LCD computer displays have a two wire interface in the cable from the video controller to the monitor. This interface is commonly known as the DDC and is used to read a block of configuration data from the display device called the EDID. These terms hide the true implementation!!
The DDC bus is simply a two wire I2C bus over the VGA cable. The EDID is read from a simple serial EEPROM device. So it can be made to work over distance with success! I have observed that often the monitor capabilities and ID EEPROM is read using PC bit banged methodology through I/Os on the video controller chip at rates in the 10-20 KHz range. Maybe the slow speed is what makes it work correctly. There is an industry consortium specification all about the DCC and EDID that tells more about this stuff. I just wanted to share that the inteface is I2C. - mkaras |
| Topic | Author | Date |
| off board i2c | 01/01/70 00:00 | |
| what are the circumstances? | 01/01/70 00:00 | |
| circumstances | 01/01/70 00:00 | |
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| Long Distance I2C | 01/01/70 00:00 | |
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| Please inform us about your results! | 01/01/70 00:00 | |
Yes, of course! | 01/01/70 00:00 | |
| checksums | 01/01/70 00:00 | |
| if you can't checksum .. | 01/01/70 00:00 | |
| Long distance I2C | 01/01/70 00:00 |