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320x240 QVGA LCDs
Posted by Chris
on
Tuesday, November 10, 2009
Here's a picture of a K838 digital photo frame, cracked open:
It basically consists of:
An AX203 microcontroller
A 2.4" LCD (320x240 pixels, QVGA, 65l colours)
Flash memory
Battery charging/protection circuit
USB plug/socket
A few crystals (one for driving the USB, one for the real-time-clock RTC)
We found similar LCD screens (the screen only, not in a nice enclosure) on eBay for about £12 each, so ordered a couple to have a play with - they may or may not use the same LCD driver chip; we'll soon find out! The LCDs on eBay also have an ingenious method of connecting the ribbon cable to the printed PCB - each exposed pin on the ribbon has a hole drilled through it. So when solder is applied to the top of the pin, a tiny dot can pass through, welding it to the PCB underneath.
Because we like working with big, fat, 0.1" breadboards and soldering to huge great big pads, we decided to have a go at building an LCD-to-DIP connector. Rather that a single line of pins, we built a double-inline-pin connector, because the LCD has no less than 36 pins to interface with. (Putting them into a two lines just seemed easier!). Bouyed by the brilliant comments on an earlier SMT project we figured that soldering to a tiny ribbon connector would be - if not easy - at least possible.
The etching on this one went a little awry. Actually, it's not as bad as it could be and the camera doesn't do the etching of the tiny fine traces justice. Although they appear blurred and merged together on the photo (highlighted on the left) each individual trace for the LCD ribbon is properly formed and complete. We should really have checked the traces leading back to the pins before etching, however, because - highlighted on the right - the connection to one of the pins has completed etched through. We'll have to patch this with a bit of silver paint or similar before testing...
It basically consists of:
An AX203 microcontroller
A 2.4" LCD (320x240 pixels, QVGA, 65l colours)
Flash memory
Battery charging/protection circuit
USB plug/socket
A few crystals (one for driving the USB, one for the real-time-clock RTC)
We found similar LCD screens (the screen only, not in a nice enclosure) on eBay for about £12 each, so ordered a couple to have a play with - they may or may not use the same LCD driver chip; we'll soon find out! The LCDs on eBay also have an ingenious method of connecting the ribbon cable to the printed PCB - each exposed pin on the ribbon has a hole drilled through it. So when solder is applied to the top of the pin, a tiny dot can pass through, welding it to the PCB underneath.
Because we like working with big, fat, 0.1" breadboards and soldering to huge great big pads, we decided to have a go at building an LCD-to-DIP connector. Rather that a single line of pins, we built a double-inline-pin connector, because the LCD has no less than 36 pins to interface with. (Putting them into a two lines just seemed easier!). Bouyed by the brilliant comments on an earlier SMT project we figured that soldering to a tiny ribbon connector would be - if not easy - at least possible.
The etching on this one went a little awry. Actually, it's not as bad as it could be and the camera doesn't do the etching of the tiny fine traces justice. Although they appear blurred and merged together on the photo (highlighted on the left) each individual trace for the LCD ribbon is properly formed and complete. We should really have checked the traces leading back to the pins before etching, however, because - highlighted on the right - the connection to one of the pins has completed etched through. We'll have to patch this with a bit of silver paint or similar before testing...
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