Twitter Updates for 20-07-2012

• Twitter Updates for 19-07-2012 – Twitter Updates for 18-07-2012 – Twitter Updates for 17-07-2012 – Twitter… http://t.co/4F6pPIVv 00:37:12, 2012-07-20
• Photo: surfdog2000: http://t.co/gEhTJzTG 02:02:37, 2012-07-20
• Hoping none of the folk I know around Denver were at that midnight showing. 13:34:11, 2012-07-20
• Gamble seems to have paid off! Camcorder contains a 0.55" LCD with connections for PAL/NTSC input. Resolution 512×218 (RGB delta dots). 14:48:11, 2012-07-20
• Note to self: lcx005bkb8 LCD with a CXA1854AR driver chip. 14:54:27, 2012-07-20
• Definitely know the ground and power wires, but the odd voltage biases on the other two confuse me. Seems to be composite though. 17:00:22, 2012-07-20
• @Muzkip :D in reply to Muzkip 18:46:42, 2012-07-20
• Note to self: 4th pin marked "HD" connects to pin 30 on CXA1854AR via a transistor. Pin marked "HD pulse output". 4th pin fed 4.3v. 20:56:12, 2012-07-20
• Definitions hard to find. May be something to do with frame timing, might be to do with high dynamic range. Overlapping acronyms. 20:57:02, 2012-07-20
• Horizontal Direction timing pulse output? Maybe transistor pulled 4.3v line low to sync camera feed with viewfinder LCD? 21:01:48, 2012-07-20
• Identifying meaning of "HD" pin on LCD viewfinder – I’m aiming to finally build a wearable, and managed to… http://t.co/NeEZyldr 23:36:02, 2012-07-20
• New blog post: Identifying meaning of "HD" pin on LCD viewfinder http://t.co/9wcVGSFb 23:36:02, 2012-07-20
• @tinycorvid I heard he was a vet suffering PTSD. Rumour mill ahoy. in reply to tinycorvid 23:59:10, 2012-07-20

Mirrored from The blog-hub for Peter "Sci" Turpin.

Identifying meaning of “HD” pin on LCD viewfinder

I’m aiming to finally build a wearable, and managed to find a cheap alternative to cutting a set of video glasses in two for a monocular. I got a broken analogue video camera off ebay that had a colour LCD viewfinder. It was a bit of a gamble that being analogue it would have simpler inputs than a digital camcorder, but it paid off. I received the camera today, pulled it apart and got it running on it’s own. 0.2A @5v with composite PAL input.

There’s a 4th pin on the connector though, in addition to Gnd, 5v and video. It’s marked “HD” on the viewfinder PCB, and I traced it back to the IC where (after going through a SMD transistor) connects to the “HD” pin 30 on the controller IC.

The datasheet for the IC expands it a little that the HD pin is for “HD pulse output”, but I can’t find anywhere that explicitly states what the HD pulse is.

I’m *guessing* it’s something to do with the frame timing since the only other HD I can find in the sheet relates to “Horizontal Direction”.

The IC is a Sony CXA1854AR by the by.

The camera supplies the HD pin on the connector with 4.3v however, or at least seems to. I thought I tested it for voltage with the display disconnected, but I’m not sure now. Rather sleep-deprived.

In any case I’m thinking it’s either a case of the IC pin using the transistor to pull the connector pin low, or more likely now that it’s actually a 5v output and my multimeter detected it at only 4.3v due to the duty cycle of the HD pulse. The HD pulse presumably would be something to sync with the video or on-screen text display. But it seems to display PAL video with no problem when it’s not in use, so unsure.

Really I’d just like it if someone can put my mind at ease on the subject. It doesn’t seem essential, but I’d like to know what it’s supposed to do.

Mirrored from The blog-hub for Peter "Sci" Turpin.