concept how to make psptouch screen

[1TONpete]

Its the avr side im questioning  about the dual nub. how do we wire both in and make it so the avr takes in data from both and can tell which is which? Program side I see the logic with "ifs". hardware, how to connect both nub and touch ? trying to get a full schematic of final diagram so we can see what else might be needed hardware wise. I'd like to be sure about what will be needed as i have to order enough supplies to build at least 5 of these. 1 will be internal on phat. 1 will be internal on slim. 1 will go full retail version on #2phat and other 2 go to devs. I'd hate to get everything i need except for "x" and have to wait another month for shipping 5 of 1 part. On the topic of shipping. Anyone know of american based suppliers of the things we need?

[galaxy3arth]

mouser.com has everything sparkfun has the touchscreen
andthe only uncertainty is the UART,because I dont know what to do for it
Post Merge: January 23, 2011, 07:34:27 PMneed booster for battery
need UART (dont know which one)
need SIO plugs
need attiny84MLF
need 16mhz crystal for what ever UART we use
need touch screen connector(sparkfun) can be used to make assembly faster no tiny soudering except the AVR
 do you know how to implement UART?
I really need help.

[1TONpete]

I have to question this. why the attiny? why not something more powerful with maybe more options? I can't give an example to improve upon this right now, but some one might know of a better chip. remember it doesnt have to be all that small. why not this http://www.sparkfun.com/products/316?

[TokyoDrift]

Oh guys I seriously don't get your problem.

We use an ATTiny84 in MLF because it's TINY (oh rly) and probably people want this mod INSIDE their PSPs
you don't need any special hardware for UART (maybe a voltage divider/resistor) because the ATTiny has this internal. look in the datasheet for the pins
the max232 is a level shifter, for connecting UART to a PCs RS232...it's not needed for PSPs
the ATTiny WILL NOT GENERATE ANY BUTTON PRESSES!
this is just not the way it's done
the only thing the ATTiny will do is listen for a "gimme the position of the touch" command and answer that
everything else is the PSP's problem
that way you don't have to update the AVR
however, we can add a bootloader to the AVR so you can reflash it using uart, we can just write an update app for the PSP then
second analog stick is approved if you get the board layout done

[1TONpete]

Tokyo , thank you for your input. I respect your knowledge on this topic as we are basing this mod on some of your work with the sio port. My reasoning for asking for a replacement of the attiny I was hoping there was a chip that can handle 2 spi's? I dont know if the attiny can do that. WE are all on a huge learning curve here. I was out of the scene for quite some time, So I've been trying to get updated info. Instead of putting out info on something i dont fully understand I ask questions. I'm also tryn to see if we can simplify our circuit with a better chip. Uart is deff. in. I didn't have a good grasp on uart but im getting there. On the same topic of uart, Isn't there a chip that also has uart already?

[TokyoDrift]

the attiny84 has an USI module inside that can be used as an UART
what would you need SPI for though? Oo

read AVR307 for USI as UART
it's kinda complicated but I guess it'll work
normal UART is easier but only available on bigger AVRs

EDIT: i guess we can also take attiny4313, that one has UART and everything and is also available in MLF20
EDIT: 4313 seems to be unavailable, use 2313

[1TONpete]

So with the attiny2313 we can connect to analog sources(touch and nub)? edit: pd is for psp, pb is for analog sources(both connect on pb)? pa is for bootloading?  Am i reading this right?"like the mlf of the attiny" good find.

[galaxy3arth]

NO the attiny4313 and 2313 do not hace adc in puts we need adc inputs
the attiny84 mlf is just fine we will just use the USI and voltage splitter.
thanks tokyo I get what your talking about now do not switch the AVR.
i will have the schematics posted by the end of the day with 2nd analog already implemented.
external UART can be used would free up some processing power.


Post Merge: January 24, 2011, 07:46:44 AMI checked all the other AVR options already the only other viable choices were the atmega series ,but they are to big.
Post Merge: January 24, 2011, 07:48:10 AMwhy would we need 2 SPIs the UART can be used for programing and is better for debugging.

[1TONpete]

Ok Ill take your word for it. I was just wondering if we were making it more complicated than it needed to be? could it be simplified by a better chip? I dont know, why i asked.

[TokyoDrift]

sorry didn't have a look at the ADC pins
there should be enough pins on ATmega84 anyways
let's not use an external uart chip, usi has to work

PIN MAP:
   XTAL1 => OSZILLATOR
   RESET => PULLUP / TESTPAD
   DI => PSP TX
   DO => PSP RX
   ADC0 => TOUCHSCREEN1
   ADC1 => TOUCHSCREEN2
   ADC2 => ANALOG1
   ADC3 => ANALOG2
   GPIO1 => TOUCHSCREEN3
   GPIO2 => TOUCHSCREEN4
   MOSI,MISO,SCK,GND,VCC => TESTPAD
   GND => GND
   VCC => VCC

That should be everything needed on the AVR. You also have to use a Boost Converter for voltage supply (provides GND+VCC) and maybe a voltage divider/resistor for the DO (to 2V maybe?)

[galaxy3arth]

if we are willing to make it a little bigger it can be. like on the atmega168/324 i beleive it has on board true UART and it has extra pins more ADC compatible, but it is pretty big( unatractive)
even if it has extra pins.
 
I think the current design is better as far as esthetics and it should function just fine.
the design is actually simpler than it sounds.
just one attiny84mlf with power source and ground
then the touch screen ribbon cable connector soudered to four ADC pins on the attiny84mlf
test pads for ICP connection (not really needed)
then a voltage splitter from the Tx and Rx of the psp to a USI compatible pin.
for second analog send the x and y values to two ADC ports left over ,and give it a power source and ground.
the booster is just for battery.
Post Merge: January 24, 2011, 08:36:17 AMtokyo is this for the attiny84mlf or are we switching to the atmega84?
Post Merge: January 24, 2011, 08:37:23 AMas for occilator I think 16mhz would be good. any input?

[1TONpete]

dumb question maybe but doesnt nub need four pins?

[galaxy3arth]

i agree with what your saying I think the USI is more complicated but more apealing than an external UART
Post Merge: January 24, 2011, 08:41:49 AMnot dumb question you just forgot that two of them are the VCC and GND the other two are the X and Y.

[TokyoDrift]

I THINK nub only needs 2 as the other 2 are connected to VCC
not sure though
touch doesn't need 4 ADCs, only 2 ADCs and 2 GPIOs
only one voltage divider is needed (AVR->PSP)
testpads are def. needed because you have to flash the bootloader to the avr
I think we should do this with dip parts on a breadboard first anyways to test everything, then we can decide about parts like the oscillator (the slower the less power it needs)

[1TONpete]

tokyo-"testpads are def. needed because you have to flash the bootloader to the avr
I think we should do this with dip parts on a breadboard first anyways to test everything, then we can decide about parts like the oscillator (the slower the less power it needs)"
-agreed.
thanks for the nub stuff. silly.
hey for slim version can we include an a/v pass through with a psp sio port on the bottom of psptouch? A/V stuff is separate from RXD ,TDX , lines correct?

[TokyoDrift]

yes, sio doesn't influence A/V, we can just pass it through as I did in my PS2 controller thing

[1TONpete]

Idea on internal mod. Take dual nub install(old way) but instead of soldering to pspmb everything is connected to sio internal (still cant find sio complete boards) , we wouldnt razorx. as long as the slim nub can be made to fit. but if its slim we have usb charge. no need for 5v in. and i believe we can turn on/hold the psp through the sio. so no need for power switch either. maybe include our own power switch? really we could remap o[]x^ to graffical touch buttons if needed so we could take out the whole right side of the psp? just a thought.

[TokyoDrift]

sounds like some massive wiring...
btw, someone should know how to fix my freeze when putting the psp to suspend...

[1TONpete]

Well normal dual nub mod requires 4 wires from nub tho psp mb. If one was going to internalize the psptouch, the nub is already connected to our board. just install where original dual nub was installed. For people who need symmetry. but put the rest of the guts of the psptouch into the area behind memory stick. And our battery should be small enough to go into the umd drive area. This project could really simplify 3 mods in one.

[galaxy3arth]

I have a small problem with designing schematic. I have 2 pin outs for the attiny84mlf one is from the atmel data sheet ,but it has pins it lists as do not connect. the other is from avrfreaks this is the one I have used so far which do I use.

[1TONpete]

if we add the pss through like planned couldnt we us txd and rxd on the pass through port also? maybe use that port to flash?

[galaxy3arth]

yeah Ill add the pass through
if there is any space left if not just add another branch to both the tx and rx
 the way the rs232 protocol works the signals should not interfere with each other as long as they are not sending the same bit assignments.
we should check into this.
Post Merge: January 24, 2011, 10:03:55 AMyeah we can do that

[1TONpete]

Back to code.... so now the avr needs to receive signals from both touch and analog. Code if touch than ignore nub? then sends code through uart , uart sends code to psp. or does uart decide which?

[TokyoDrift]

you can't pass through the uart lines
it doesn't work

AVR should always do both, PSP decides what data to request

[1TONpete]

code would need loop both control types then correct?
not say pass through uart sorry, not sure on how to word what im thinking. pass the a/v through normal wires to our external psp sio port. directly from the the psp to the sio port. the use the remaining pins to run leads to flash our chip. no extra port needed?


We dont really need touch when displaying video out, and we dont need video out to program, so the a/v stuff could all be separate.

[TokyoDrift]

we're gonna have a usi bootloader on the AVR (someone should write that?)
then the PSP can flash the avr
you can pass through the signals for video out, not the sio signals though

[1TONpete]

not trying to say pass through sio signals. tryn to say use remaining pins for video out sio on psptouch to program our avr. the video out doesnt need comm pins so we can use those pins to program.
like the idea of psp flashing avr. I dont know how to write that. (yet)
basically your idea with the extension cable. splice cable so it splits video and data. the psp'sio data goes to the psptouch hardware. the psp's sio's video goes straight through unchanged. the psptouch's sio port will then have open pins. use remaing pins to send reflash data to the psptouch's avr.

Post Merge: January 24, 2011, 11:37:22 AMhow hard would it be to keep full functionality on the psptouch's sio port? say like using a remote /charging/video dock. remote is handled through sio data , so idk?

[TokyoDrift]

hard enough to make me have no idea about where to start
we'd have to get information about big parts of the PSP firmware I think, I doubt it's possible
reflashing from the PSP should be quite simple
PSP can send a cmd to the avr to make it jump to bootloader mode, then just upload the hex file, reset the avr, done
we need to write a usi uart bootloader for the avr though, doubt there is one already

[1TONpete]

I think we can worry about that for updates after beta is released. we're building breadboard first anyways so for dev purposes flash from programmer for now. Homebrew could be made to reflash the avr later.
As far as bootloader  from psp. pretty sure this page holds the key to everything. -Tyranid- http://www.docstoc.com/docs/28752025/psp.
everyone involved shoud read this . I might print it up so i can study it over and over. From my understanding we can make it so the psp does most of the work. Pspsdk is all I got to say.

[galaxy3arth]

there are only four/five pins left on the AVR
for the reset to load into boot loader mode we can just take the reset pin and connect it to an IO pin so that the AVR program can give voltage to the reset to get into boot-loader mode after a signal for that pin is received could you guys do this.
that leaves us with three pins left.
Post Merge: January 24, 2011, 12:35:58 PMany thing you want me to do with the remaining pins?