bluehash 1,581 Posted April 17, 2013 Share Posted April 17, 2013 Buy Spirili's Nokia 1202 LCD BoosterPack from The 43oh Store. Group Buy Link. This is outcome of the Powerscope project. The Powerscope, maintained by @@mechg, uses a slightly expensive PCB. It's gorgeous, don't mean to downplay it. But in the search for a lower cost one, @@Sleepwalker3 mentioned about the Nokia 1202 LCD display that were being used in the dangerous prototypes forum thread. As a first pass, I created this boosterpack. It really does not need any components on it, just the LCD. The BoosterPack was designed so that it can be used with other microcontrollers too via a breakout header. Need to fix. - Missed out on adding component labes. 43oh_BP_Nokia_1202_v1.0.zip Quote Link to post Share on other sites
mbeals 74 Posted May 13, 2013 Share Posted May 13, 2013 is there some documentation or design notes on this board? I'm particularly curious about the transistor with the LED cathode attached to the base and the MCU pin on the collector Quote Link to post Share on other sites
bluehash 1,581 Posted May 13, 2013 Author Share Posted May 13, 2013 is there some documentation or design notes on this board? I'm particularly curious about the transistor with the LED cathode attached to the base and the MCU pin on the collector No doc as of yet. The schematic is in the first post. I'll let you know when I reach home. Quote Link to post Share on other sites
spirilis 1,264 Posted May 20, 2013 Share Posted May 20, 2013 Ok I d/l'ed Eagle to view the schematic and .brd file, took a pic of the boosterpack and annotated it for quick reference: Not too sure about the LCD reset line, it's attached to both P2.1 and the RST pin on the right header of the LaunchPad... wouldn't setting P2.1 low to forcibly reset the LCD also reset the MSP430? P2.1 is solder-jumpered but the LCDRST<-->LP RST is not unfortunately. Also wouldn't mind having some pads broken out next to the LP header pins so I can effectively rewire the SPI MOSI to P1.7 (USCI-style) instead of the board's default P1.6. Can always do that to the exposed lead after soldering the female headers on though. edit: I see why now, it uses 9 bit SPI D'oh! That said, I do love me some G2452's... cubeberg and bluehash 2 Quote Link to post Share on other sites
mbeals 74 Posted May 20, 2013 Share Posted May 20, 2013 Traditionally wouldn't you connect the mcu pin to the transistor base and the LED cathode to the collector (opposite of what is in the schematic)? Unless there is a trick I don't know about transistors, I don't see how this is switching the backlight. RobG and spirilis 2 Quote Link to post Share on other sites
spirilis 1,264 Posted May 20, 2013 Share Posted May 20, 2013 Traditionally wouldn't you connect the mcu pin to the transistor base and the LED cathode to the collector (opposite of what is in the schematic)? Unless there is a trick I don't know about transistors, I don't see how this is switching the backlight. I didn't catch that when I was looking at it... Oops. Yeah guess that backlight is pretty useless with this Quote Link to post Share on other sites
cubeberg 540 Posted May 20, 2013 Share Posted May 20, 2013 I didn't catch that when I was looking at it... Oops. Yeah guess that backlight is pretty useless with this The schematic is off - but if you look @ the board - it looks like it might work correctly (depending on the pinout of your transistor). Did @@bluehash make the board? Maybe he couldn't find the correct footprint for the transistor he was planning on using? Quote Link to post Share on other sites
mbeals 74 Posted May 20, 2013 Share Posted May 20, 2013 I've never seen a transistor that didn't follow the standard 'boys eat cheese' layout, which would place the base at the top left, the emitter connected to ground and the collector running to the pins on the bottom right. If someone did design some non-standard pinouts for cases like this, it would sure come in handy. Quote Link to post Share on other sites
cubeberg 540 Posted May 20, 2013 Share Posted May 20, 2013 I've never seen a transistor that didn't follow the standard 'boys eat cheese' layout, which would place the base at the top left, the emitter connected to ground and the collector running to the pins on the bottom right. If someone did design some non-standard pinouts for cases like this, it would sure come in handy. Yeah - I was just looking at that - couldn't find one that followed that pinout. Probably still possible to bodge a transistor onto it though - put it on at an angle or blue-wire it. Had to install some upside-down on one of my boards that I messed up - was pretty easy. Quote Link to post Share on other sites
spirilis 1,264 Posted May 20, 2013 Share Posted May 20, 2013 The way I know those SMD SOT transistor footprints, I don't see how you can do it. Maybe putting it upside down and twisting the legs around a bit... Alas this was a first draft of the concept so a revision 2 should be in order soon :grin: I do like the price point of those + solderability, after I get mine working I might see about going in on an order of 20 from aliexpress. Quote Link to post Share on other sites
mbeals 74 Posted May 20, 2013 Share Posted May 20, 2013 i wonder if you flip it along the long axis (upside down) and rotate 45* clockwise. That would put the pins in the proper order and might put them close enough to the pads to solder without heroic measures. Quote Link to post Share on other sites
cubeberg 540 Posted May 20, 2013 Share Posted May 20, 2013 i wonder if you flip it along the long axis (upside down) and rotate 45* clockwise. That would put the pins in the proper order and might put them close enough to the pads to solder without heroic measures. Yep - I remember running across across a post somewhere where they did that - rotating it puts the pins in just about the right position. Quote Link to post Share on other sites
spirilis 1,264 Posted May 21, 2013 Share Posted May 21, 2013 Soldered mine up- Chose to switch SPI over to the USCI layout. I'll do a bitbang hack or something to get it working. It'll work out of the box with my Renesas boards anyhow. The transistor-upside-down hack worked OK, although I haven't actually tried powering it up yet. . . but with tweezers holding the transistor I was able to rake its pins upside down, then used my new lead-based solder paste on the pads and it sunk down in the blobs pretty well. Soldering the display was easy, although my alignment was slightly off but I don't think there are any shorts. Excited to give it a test run soon! Quote Link to post Share on other sites
mbeals 74 Posted May 21, 2013 Share Posted May 21, 2013 How did you solder the display? I'm wondering if it will be easier to tin the pads and try to reflow it or just flux the crap out of it and try and get the solder to wick under Quote Link to post Share on other sites
spirilis 1,264 Posted May 21, 2013 Share Posted May 21, 2013 Tinned the pads on the PCB, applied flux to those pads + the pads underneath the connector, lined up the connector with a little lip of the PCB pad exposed (might make the pads in my own footprint a little longer so it fits flush with a slight lip) and touched the PCB pad first, that reflowed some of it... then pressed the iron on the tiny via in the connector for that pad to help get the heat deeper into the middle of the pad. Did that back and forth with all the pads until they looked good. Probably takes longer to explain than to do Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.