Take over the amazing control panel of a vintage video mixer

Where does he find such wonderful toys? [Glenn] extracts from a Grass Valley Kalypso 4-M / E video mixer eBay’s switch control surface and since then he has reverse engineered the button and display modules to bend them to his will. The material dates from the turn of the century and the two modules would have been arranged with a few dozen others to complete a video mixed switching console.

[Glenn’s] previous adventures have looked at a strip of ten backlit buttons and give us an overview of each of the keyswitches and the technique they used to put together their own pinout and schematic for that strip. But things are getting a lot hairier this time around. The long strip seen above is a “machine control plane” module and includes a dozen addressable character displays, driven by a combination of microcontrollers and FPGAs. The square panel is a “Crosspoint Switch Matrix” module comprising eight individual 32 x 32 LCD screens driven by three dedicated integrated circuits which can be displayed in red, green or amber. [Glen] used an STM8 Nucleo 64 to interface with the panels and wrote some code to help map what each pin of each connector on the machine control plane could do. He was able to broadcast some packets from the plane that changed when he pressed buttons, and ended up sending back a brute force of that packet format to understand LED display protocols.

But the LCD screens on the cross point switch were a harder nut to crack. He ended up going back to the original source of the equipment (eBay) to get a working control unit that he could sniff. He laid out a man-in-the-middle card that has a connector on each side with a pin header in the middle for his logic analyzer. As with most LCDs, the secret sauce was the boot sequence – something almost impossible to force abruptly, but extremely simple to sniff out when you have a working system. So far it’s been running them under USB control, and if you’re lucky enough to have some of that gear in your parts box, [Glen] has painstakingly recorded all the details you need to make them work.

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