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Connecting to a QVGA LCD
Posted by Chris
on
Thursday, November 12, 2009
Well yesterday morning a parcel arrived containing one of these little photo frame jobbies. We plugged it in and tried it out - very nice. The image quality is great (though the refresh rate looked a little disappointing - you could visibly see the screen updating, and it took 1-2 seconds to draw an entire full-screen image).
No matter, what we needed to do was crack the thing open and get stuck in, just like Xing had done with his, in order to send us these photos.
Once it was open, the first thing to do was to get the LCD ribbon off the PCB.
This was actually easier than first anticipated, following the sage advice of Robot Steve. Simply put, we followed his diagram and heated the solder connecting the pins to the ribbon, by heating *behind* the ribbon connector - applying the iron to the connections on the PCB, not the ribbon itself.
By starting at one end, and with a wide chisel-tip on the iron (wide enough to heat four pins at a time) we could reflow the solder and gently lift the ribbon clean off the PCB. It came of quickly and easily with no broken pins, traces or connectors. Brilliant!
We then laid the ribbon across our own PCB breakout board.... and found we'd made our traces too small. The ribbon was far too wide. Bugger. That meant we had to make up a new PCB (not actually a bad thing, since our earlier effort had a few broken traces anyway). An hour or so later and we'd managed to etch a couple of new breakout boards (its always worth having one spare, just in case). This time, the traces on the PCB and the connectors on the LCD ribbon lined up perfectly.
The ribbon was connected by using the same wide chisel-tip, and running the iron quickly across the top of the ribbon, flowing the solder onto the homemade PCB breakout board. Luckily there was enough solder left on the ribbon to connect pins to our PCB.
The last thing to do was connect the pin headers to the 2 x strips of 18-holes and see if we could get the thing to switch on. That's where we're up to now (it was a late one last night, getting the ribbon connected onto the PCB). Although we don't know the initialisation sequence, at this stage, it'd just be nice to see a backlight or something come on, if only to show we haven't made a mess of soldering the ribbon cable to the PCB board!
We've checked and double-checked all the pins for continuity, and checked that there are no shorts across the pins (they're tiny little traces in case you hadn't noticed!) so in theory it should work first time.........
No matter, what we needed to do was crack the thing open and get stuck in, just like Xing had done with his, in order to send us these photos.
Once it was open, the first thing to do was to get the LCD ribbon off the PCB.
This was actually easier than first anticipated, following the sage advice of Robot Steve. Simply put, we followed his diagram and heated the solder connecting the pins to the ribbon, by heating *behind* the ribbon connector - applying the iron to the connections on the PCB, not the ribbon itself.
By starting at one end, and with a wide chisel-tip on the iron (wide enough to heat four pins at a time) we could reflow the solder and gently lift the ribbon clean off the PCB. It came of quickly and easily with no broken pins, traces or connectors. Brilliant!
We then laid the ribbon across our own PCB breakout board.... and found we'd made our traces too small. The ribbon was far too wide. Bugger. That meant we had to make up a new PCB (not actually a bad thing, since our earlier effort had a few broken traces anyway). An hour or so later and we'd managed to etch a couple of new breakout boards (its always worth having one spare, just in case). This time, the traces on the PCB and the connectors on the LCD ribbon lined up perfectly.
The ribbon was connected by using the same wide chisel-tip, and running the iron quickly across the top of the ribbon, flowing the solder onto the homemade PCB breakout board. Luckily there was enough solder left on the ribbon to connect pins to our PCB.
The last thing to do was connect the pin headers to the 2 x strips of 18-holes and see if we could get the thing to switch on. That's where we're up to now (it was a late one last night, getting the ribbon connected onto the PCB). Although we don't know the initialisation sequence, at this stage, it'd just be nice to see a backlight or something come on, if only to show we haven't made a mess of soldering the ribbon cable to the PCB board!
We've checked and double-checked all the pins for continuity, and checked that there are no shorts across the pins (they're tiny little traces in case you hadn't noticed!) so in theory it should work first time.........
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