Content deleted Content added
m →D-PHY: added comment about using D-PHY below 500 Mbps -> less power efficient |
m →D-PHY: rephrasing for readability |
||
Line 47:
Versions 1.0 and 1.1 of UniPro use MIPI's D-PHY technology for the off-chip Physical Layer. This PHY allows inter-chip communication over printed circuit board traces as well over roughly 20 cm of cabling. Data rates of the D-PHY are variable, but are in the order of 500-1000 Mbit/s (lower speeds are supported, but at decreased power efficiency). The D-PHY was named after the Roman number for 500 ("D").
The [[D-PHY]]<ref>[https://members.mipi.org/mipi-adopters/file/Specifications/Board%20Approved/MIPI%20D-PHY%20Specification_v00-90-00_final_11152007132023.pdf MIPI D-PHY 0.90 specification],requires an account at the MIPI website</ref> uses differential signaling to convey PHY symbols over micro-stripline wiring. A second differential signal is used to transmit the associated clock signal from the source to the destination. The D-PHY technology thus uses a total of 4 signal wires per direction.
In UniPro, the D-PHY is used in a mode (called "8b9b" encoding) which conveys 8-bit bytes as 9-bit symbols. The UniPro protocol uses this to represent special control symbols (outside the usual 0 to 255 values). The PHY itself uses this to represent certain special symbols that have meaning to the PHY itself (e.g. IDLE symbols). Note that the ratio 8:9 can cause some confusion when specifying the data rate of the D-PHY.
| |||