Update

Well not that much has happened, I have connected up the 3 output HDMI sockets to the chip, now just to wire up the input. I will not win any awards for the prettiest device. The way I have connected up the function pins that control the logic should allow to easily connect the the GPIO pins and power will be from the GPIO pins as well. I hope to have time during the next week to sort out the input and then I should be able to try things out. 

I have also been thinking about the proper prototype PCB and getting it built, I have found some good sites, they are mainly outside the UK so will take extra time to deliver. I intend to bring all the CEC pins to a header and use jumpers to select which will connect to the TV. Depending on the time I might try to automate this and include a matrix switch do it will always follow the device connected to the TV, or just try to find a way that all the CEC pins are connected together. 

Proof of Concept

Well I have started to sort out a design. I managed to get a sample IC sent Free from TI, I was surprised as it was sent via DHL from USA to the UK within a few days. But the bigest surprise I had was that the IC was packaged in a moisture free package. I have been in electronics for a few years now and have not come across a moisture sensitive IC, unless it was designed to measure moisture. After a bit of digging I found the reason to be the size and pitch of the IC pins. The device is a 64 pin TQFP package, this means the IC has small pins, very small. The design and production of this is going to be tough, but fun.

To speed up the development I managed to find a PCB that is used as a adapter to convert a QFP device to a standard IC pin pitch and size. Luckily the design only has a few components so fitting it all into a proof of concept should be easy enough.

The only other part missing from the concept is a connectors. Unfortunately I could not find a easy was to mount 4 HDMI sockets on the PCB, or any PCB that they could mount onto. So I did the next best thing and bought 3 HDMI extension leads and cut them up so I could solder the leads to the PCB directly. I have now found out that you do get what you pay for, the leads I bought where from Amazon, and I found out after I cut it up it was not fully wired. I was not expecting HDMI 1.4 spec but I was expecting the CEC pin to be connected. This means the concept will not have CEC, which is sort of ok for now, I will look at buying some different cables and used them to wire up the CEC part of the concept system.

Now for the job of hand soldering the 64 pin TQFP IC.....     

First post

After spending time playing with my Raspberry Pi and having connected to my TV, I found it a pai to keep moving HDMI leads about. My TV only has 2 HDMI ports, 1 has the DVD/Sat connected to and the other has the PS3. I Normally connect the RPi to the HDMI port the PS3 is connectes to. But I don't always connect it back and then when my wife goes to use the PS3 she can't, and then get moaned at.

So I looked at HDMI Switches, these plug inline with the the HDMI lead to the TV and take 2 to 4 inputs. Selection of the inputs can be automatic or via a switch. What I find is a pain is having to go to the TV and use the switch to select the RPi. I use the RPi as both a media server and general LINUX usage. This got me thinking about connecting up a HDMI switch to the RPi and control the switch from the RPi. This is then the birth of PiSwitch.

PiS is a 3 to 1 HDMI switch controlled via 2 GPIO pins. It is based around a Texas Instruments TDMS361B. This blog will detail my journey in the development of the switch.