CSI-2 to HDMI
It is possible to use an HDMI cable to extend the lead on the Pi Camera CSI-2 connection, but some lower quality HDMI cables will not work (and do not allow the camera to start up) without modifications to the Tindie connector cards https://www.tindie.com/products/freto/pi-camera-hdmi-cable-extension/. This is because some cables do not include the ground/shield connection for the 4 data pairs, and some do not include a wire for the Consumer Electronics Control (CEC) channel on pin 13.
There are 2 modifications required:
The first modification uses the overall cable screen to replace the non-existent data pair screens. To make this modification, simply use solder to bridge the 2 rectangular pads above to the "GND" caption on the right hand side of the HDMI socket. Thanks to Tindie and his blog http://petitstudio.blogspot.co.uk/2015/05/hdmi-cables-are-not-all-same.html for this modification.
The second modification uses one of the spare cores (labelled a, b, c and d) instead of the possibly non-existent Pin 13 CEC core. This modification requires a fine soldering iron and a magnifying glass to solder a wire between pin 13 on the CSI-2 flat cable connector (coincidentally connected to pin 13 on the HDMI connector) and the round pad labelled "d". Use a test meter to check that you have not created a solder bridge to pin 12 or pin 14 after making this modification. I chose the "d" pad because this is a data wire in the normal usage of HDMI.
Of course, these modifications need doing at both ends of the cable
The unmodified board, and the 2 modifications are shown below.
The HDMI pins are numbered from 19 on the left to 1 on the right in the images. The CSI-2 connector pins are numbered from 1 on the left to 15 on the right. The detailed pinout is below for reference.
| CSI-2 Pin | Name | Purpose | Tindie PCB | HDMI Pin | HDMI Name |
|---|---|---|---|---|---|
| 1 | Ground | Ground | Ground | 11 | Ground |
| 2 | CAM1_DN-0 | Data Lane 0 | 12 | TMDS Clk - | |
| 3 | CAM1_DP0 | Data Lane 0 | 10 | TMDS Clk + | |
| 4 | Ground | Ground | Ground | 8 | Ground |
| 5 | CAM1_DN1 | Data Lane 1 | 9 | TMDS 0 - | |
| 6 | CAM1_DP1 | Data Lame 1 | 7 | TMDS 0 + | |
| 7 | Ground | Ground | Ground | 5 | Ground |
| 8 | CAM1_CN | MIPI Clock | 6 | TMDS 1 - | |
| 9 | CAM1_CP | MIPI Clock | 4 | TMDS 1 + | |
| 10 | Ground | Ground | Ground | 2 | Ground |
| 11 | CAM_GPIO | 3 | TMDS 2 - | ||
| 12 | CAM_CLK | 1 | TMDS 2 + | ||
| 13 | SCL0 | I2C Bus | 13 | CEC | |
| 14 | SDA0 | I2C Bus | 14 | Reserved | |
| 15 | +3.3v | 15 | DDC | ||
| a | 19 | Hot plug | |||
| b | 18 | +5v | |||
| c | 17 | Data Shield | |||
| d | 16 | DDC |