Ray, have you thought of making the pcb slightly larger which sandwiches between the case top & bottom? I often do this as it actually makes it an easy mount in some standard boxes.
Just some thoughts ... One tough thing will be getting the LCD to rest squarely against components. Why don't you add a dual footprint for the FLASH / SDCARD? I would be inclined to let Brad's USB serial port handle communications. The FTDI is fine, but as you know, it's a PITA and is taking lots of space.
My new designs are hopeful that we can get USB to function using the prop and no FTDI chip. If it works, then a USB command can be used to cause a reset provided the USB cogs have not frozen.
Ray: I have used a larger pcb which sandwiches in between the two shells of the case - the pcb actually fits in between the case but extending outwards to the outer edge of the case making the case 1.6mm (pcb thickness) thicker. Of course this depends on the pcb being at the point of the case join. Its just a suggestion that may work.
New PCB layout is finished (I think). This one was a real challenge, but I think I have everything hooked up. I'm just upset that I didn't make the 2PM deadline for ExpressPCB and now have to wait until Monday for the boards...
New PCB layout is finished (I think). This one was a real challenge, but I think I have everything hooked up. I'm just upset that I didn't make the 2PM deadline for ExpressPCB and now have to wait until Monday for the boards...
Got the boards yesterday and started soldering it today... First, I got the FTDI chip talking over USB. Then, I added in the voltage regulator, then the Propeller. Then, the LCD. Put in the 24 MHz crystal for the Prop.
Prop is working fine. Am able to use fullduplexserial with the attached PC.
But, I haven't been able to get the screen working yet... My pins are all different from jazzed and I actually have P0..P7 going to D7..D0 (for ease of routing), which makes converting his code difficult.
I am able to set and read a 2-bit ID from the LCD, so I think I'm on the right track...
BTW, I ordered some red ones from J&R, which turned out to be a mistake because they have a completely different PCB and LCD. And, the LCD part number comes up with nothing on Google, so that's a dead end...
I remember having trouble getting this to light up before. I could take a day or two to help you get this working with my driver which if nothing else would confirm your design will function. I think you have my address - PM me if not.
I sense that you wouldn't want to use my driver which is fine since I see things that I would do differently too , but I've made this work before. So, here I am if you get stuck.
BTW, I'm pretty sure I have D0-7 connected to P0-7.
jazzed, thanks, I may need your help. I have no idea why it's showing a blue screen.
I'm using the same pins for data, but in reverse order from what you had. That's the problem... Your driver code looks fine.
I have a few spare boards now. I can send you one, if you want. There are just a few issues with them. Most noteably, I had the pin order backwards on the USB connector when I moved it to the bottom layer. So, it needs some knife work and jumper wires...
This thing was really driving me crazy! I just couldn't get the display to do anything... So, I figured it was damaged somehow. Opened up another white and black Coby and wouldn't you know it, they each had a completely different display. The boards are the same though, so that's good. I melted the white one's display trying to get it off with a hot air gun.
Got the new black one's display off intact, but after hours and hours, couldn't make the thing work. Figured I may have broke it so I took it off my board and put it back on the original board and it still worked. put it back on my board and after hours and hours finally got it working yesterday
But, I'm a little troubled because I'm not sure why this 10th or so try at a driver works and all the other ones don't. I think it's something in the init sequence, but not sure what...
But, I'm a little troubled because I'm not sure why this 10th or so try at a driver works and all the other ones don't. I think it's something in the init sequence, but not sure what...
It does seem to work every time now. And my previous attempts still don't work...
This display is part# TXDT144C-7735R
Found this number on a website and it appears to be a TFT display, which is actually better than the other CSTN one. Can't find a datasheet for it though...
I've attached my new driver/test code. It's in SPIN. I'll convert it to Assembly soon...
Haven't tried the flash at all yet although I do have it soldered in... I also have a tiny RTC chip to test out. I put in the pads for a tiny speaker, but haven't actually ordered that yet...
I'd like to put in an 3-axis accelerometer chip, but I don't know if there's room...
My real problem right now is the buttons... My original plan isn't working because the LCD pushes down on the buttons which pushes them into the plastic bottom of the switches, which then won't let the switches push in... But, I did find some really tiny switches on Digikey that I'll try. It's either that or take a knife to the buttons...
Using the straight ROM font, that's right. But, jazzed has already used a smaller font with it. I hope to have the "Graphics.spin" vector font working with it soon too...
I can also bring over a few smaller fonts from my PSM code...
I have noticed that there are now plenty of 1.5" keychains available in Australia for $10. Not sure if they are the same.
As I said earlier in this thread, I bought a 2.5" version ($20?) that used the same chip so it should be easy for me to get this going when time permits. I would rather a larger screen.
Graphics Demo! Screen update is very fast (Now have 5 MHz crystal installed).
There's a video in the attached zip file.
When they were ~$20 I was able to resist the temptation to hack these things... But, now that they're <$10, it was too hard for me not to crack them open...
PS: Just opened up a Blue one from Amazon. It has the original COG type LCD with the same circuit board. I think I'll see if this display will work with the new driver too... I have a guess that they made the different LCDs perfectly compatible so that no changes to the board design or firmware had to be made...
I think I just thought of a way to use this as a PropPlug. There's a PropPlug 4-pin header on the bottom of the board. It's there in case the FTDI USB chip didn't work out. But, since the FTDI chip works, you should be able to plug this board to any other Prop board as if it were a Prop Plug.
Only problem is that the reset line would reset this board as well as the one you want to program. But, what I can do is put in a resistor between the reset transistor and the Prop's reset pin. Then, I can run a new wire between the Prop's reset pin and one of the three buttons. Then, you can just push the button to prevent reset. So, you can just push a button to use this thing as a Prop Plug.
Lol, a visual prop plug for less than $20? I spotted those Coby's in Frys and was very tempted, but "didn't". Must not until I've put my Zipit2 back together.
Does the reset issue prevent us having a fancy bar graph as the target prop is programmed?
Bar Graph indeed Waiter! I'll have another Manhattan! ... Oops, wrong bar.
The Propeller could be configured as a FIFO with extra pins connecting to the other device.
I'd like to sell just the boards, but I doubt that would help anybody because the LCD is difficult to remove without special tools.
I'd like to do a short run of 16 or so units, but have a few problems:
1. The cost is likely to be $30 even if I don't make any money off of it.
2. There seems to be a different type of display in almost every unit I open. This means several different versions of the initialize routine. And, I've yet to get the CSTN working right.
3. I'm not sure I'll get the switches working right with the case closed flush.
Ray, what about the larger 2.5" version like I have. Are they easy to find in the US? There is more room in these units and they have a nice battery (LiPo?) which could be replaced with a pcb. IIRC I attached a photo in my post earlier in this thread. I just think a larger version would be more practical provided the units can be obtained readily and cheaply. IIRC Officeworks (in Oz) have plenty of them at $20??
In one of the projects I have planned, I will be buying generic housings, LCD's, etc.... so that I can control the components. Of course the primary product volume will be high enough so I can harvest the economy of scale as a secondary beneficiary. I bet that you could buy everything except the PCB but the parts in total may actually cost more than the finished product.
Comments
BTW: I've started the schematic and layout for the board... Here's what I've got so far:
Ray: I have used a larger pcb which sandwiches in between the two shells of the case - the pcb actually fits in between the case but extending outwards to the outer edge of the case making the case 1.6mm (pcb thickness) thicker. Of course this depends on the pcb being at the point of the case join. Its just a suggestion that may work.
Prop is working fine. Am able to use fullduplexserial with the attached PC.
But, I haven't been able to get the screen working yet... My pins are all different from jazzed and I actually have P0..P7 going to D7..D0 (for ease of routing), which makes converting his code difficult.
I am able to set and read a 2-bit ID from the LCD, so I think I'm on the right track...
I sense that you wouldn't want to use my driver which is fine since I see things that I would do differently too
BTW, I'm pretty sure I have D0-7 connected to P0-7.
I'm using the same pins for data, but in reverse order from what you had. That's the problem... Your driver code looks fine.
I have a few spare boards now. I can send you one, if you want. There are just a few issues with them. Most noteably, I had the pin order backwards on the USB connector when I moved it to the bottom layer. So, it needs some knife work and jumper wires...
Ok
It should be easy enough to use "REV data,#24". Unfortunately there is no
one subroutine for read or write since I was focusing on performance.
What extra parts are necessary to stuff the PCB?
Got the new black one's display off intact, but after hours and hours, couldn't make the thing work. Figured I may have broke it so I took it off my board and put it back on the original board and it still worked. put it back on my board and after hours and hours finally got it working yesterday
But, I'm a little troubled because I'm not sure why this 10th or so try at a driver works and all the other ones don't. I think it's something in the init sequence, but not sure what...
This display is part# TXDT144C-7735R
Found this number on a website and it appears to be a TFT display, which is actually better than the other CSTN one. Can't find a datasheet for it though...
I've attached my new driver/test code. It's in SPIN. I'll convert it to Assembly soon...
Graphics Demo is next!
Looking good.
I just love the fact that you don't have to use propeller memory to do video and 65K simultaneous colors are possible.
Having any luck with the built-in Flash?
I'd like to put in an 3-axis accelerometer chip, but I don't know if there's room...
My real problem right now is the buttons... My original plan isn't working because the LCD pushes down on the buttons which pushes them into the plastic bottom of the switches, which then won't let the switches push in... But, I did find some really tiny switches on Digikey that I'll try. It's either that or take a knife to the buttons...
Looks like one can display 4 lines of 8 characters, yes?
Harley Shanko
I can also bring over a few smaller fonts from my PSM code...
As I said earlier in this thread, I bought a 2.5" version ($20?) that used the same chip so it should be easy for me to get this going when time permits. I would rather a larger screen.
There's a video in the attached zip file.
When they were ~$20 I was able to resist the temptation to hack these things... But, now that they're <$10, it was too hard for me not to crack them open...
PS: Just opened up a Blue one from Amazon. It has the original COG type LCD with the same circuit board. I think I'll see if this display will work with the new driver too... I have a guess that they made the different LCDs perfectly compatible so that no changes to the board design or firmware had to be made...
Only problem is that the reset line would reset this board as well as the one you want to program. But, what I can do is put in a resistor between the reset transistor and the Prop's reset pin. Then, I can run a new wire between the Prop's reset pin and one of the three buttons. Then, you can just push the button to prevent reset. So, you can just push a button to use this thing as a Prop Plug.
Does the reset issue prevent us having a fancy bar graph as the target prop is programmed?
The Propeller could be configured as a FIFO with extra pins connecting to the other device.
I'd like to do a short run of 16 or so units, but have a few problems:
1. The cost is likely to be $30 even if I don't make any money off of it.
2. There seems to be a different type of display in almost every unit I open. This means several different versions of the initialize routine. And, I've yet to get the CSTN working right.
3. I'm not sure I'll get the switches working right with the case closed flush.
4. I'm not actually sure if there's any demand...