What to do?

[benryves]

The 08M has switchable input/output lines, meaning that it can be directly hooked up to the TI without external circuitry. Another advantage of using two chips is that the 18X could be waiting for serial input whilst the 08M is still sending data to the TI.

The 08M can only run at 4MHz or 8MHz (adjusted with the SetFreq command). SerTxd sends out serial data at 4800 baud, so when running at 8MHz this becomes 9600 baud, good for the MP3 player.

[rcfreak0]

Thanks for the more info. Well at least the 08m was worth somthing . Ill see if i can order the 18X PICAXE this weekend, but i dont have a protabaord for that. So would i have to rig up my breadboard to do data transfers?

Im leaving comp class now, ill be back on in 3-3.5 hours

--rcfreak0

[benryves]

Yep. This is why I built the power supply/serial cable circuit (the few resistors and push button) on a small bit of stripboard so I can easily plug it into any circuit. :)

The 18X could talk to the 83+; you might get away with a simple resistor between the input and output pins. I'm not sure of that, though. I suggest you look at the link protocol guide to see what I'm on about when it comes to communicating between the TI and the PICAXE (or any other component).

EDIT: I posted on the PICAXE board looking for suggestions - supposedly two new chips are coming out that would be more appropriate (see thread here) so it might be worth waiting a bit. As I said, the 08M should be able to control the MP3 player on its own, it's the reading back of data that's the difficulty.

[rcfreak0]

Oh, ok. Ill wait for a bit, and just work with what i have for now. Im still saving money for the mp3 player, so i/we have a bit of time. My schools blocked that sites forums, so ill TRY and check it tonight. I AM grounded so i dont know how much ill be on this weekend, but Im gonna try to get on at least once. IF i have to (hopefully i wont) i will just run the mp3 player with e 08M and just pick from hearing the song, i dont want to do this, so im gonna try and convince my parents to let me get more PICAXE chips when they come out. BUT what about the PICAXE chips higher than 18X? i thought their were some, and if their is, would any of those work?

--rcfreak0

[benryves]

Look in the BASIC manual to see what is and isn't offered on the various chips.

To play an MP3 you need to send a complete command to the MP3 player, telling it the path of the file to play (look at the MP3 player manual for details). To get that name you'd have to receive data from the MP3 player (or type it in blindly).

Personally, I don't want you to waste a large amount of money on something that wouldn't work (I'd recommend experimenting with the parts you already have - if you can get a feel for the PICAXE BASIC and development, that would be a good thing - to test the link Telnet 83+, available on ticalc.org, is invaluable). I will not be able to develop the TI program (I haven't the time) and wouldn't be able to test any PICAXE program (I'm not shelling out on the MP3 player myself) so if I were you I'd make sure I was comfortable with what I was doing with the cheap parts before diving into the expensive parts.

The MP3 player does have an alternative interface, where you can play one of 127 songs using a basic parallel interface, but that's even less flexible than the PICAXE-friendly MP3 player available from Revolution. You'd really want the serial interface, and that's going to take some working at.

[rcfreak0]

Goody, this is going to be harder than expected. Im gonna think about my options and see what to do. I dont blame you for not wanting to shell out for the mp3 player (too expensive!). Ill post on monday about my decision. Im still going to try inferencing stuff with my calc and the 08M. If you have any ideas on what else to inference let me know.Thanks for all the info.

--rcfreak0

[benryves]

Not sure if the PICAXE site is still blocked from your end, so here's a post from their technical team:

[rcfreak0]

Hey, that might just work. Im just wondering how it would be powered on-calc, and how big it is. Otherwise, im gonna keep looking into that, it might just work. Plus its ALOT cheaper. Thanks for the suggestion. More post later.

--rcfreak0

EDIT:
I just found all the schematics and everything.

EDIT agian:
So he 28X1 PICAXE is what i would need to control the VMusic2 MP3 device? If so let me know and once i get paid, ill order everything. Be back on later

[benryves]

The 28X1 was the recommended PICAXE for communicating with the original MP3 player you were thinking of getting. The cheaper USB flash drive MP3 player doesn't need to be controlled serially (you can send data using its own protocol where the PICAXE controls the timing) so you could get away with a slow, low-end PICAXE (maybe even fit the routines onto a single 08M).

I'd need to look over the datasheets more carefully, to inspect the VMusic2's protocol a bit better.

[rcfreak0]

OK, so i might not have to order any more PICAXE chips, thats cool. The 08m might work right? If this mp3 player will work let me know what i need to control it (if i dont have it already) and ill order everything.
Thanks again,

--rcfreak0

[benryves]

I had a quick look through the beta BASIC manual for the new parts, and summarised a list of some of the rather groovy new 28X1/28X2 features:

• Scratchpad variable space (128 or 256 bytes).
  
• Better arithmetic (SIN, COS, SQR, INV, NCD, DCD, BINTOBCD, BCDTOBIN).
  
• Calibration of the internal ADC (CALIBADC, CALIBADC10).
  
• Disable checking for downloads (DISCONNECT/RECONNECT).
  
• DOZE low-power sleeping (but keeps stuff running in the background), HIBERNATE.
  
• Hardware I²C routines.
  
• Advanced hardware serial comms (HSERIN, HSEROUT, HSERSETUP).
  
• Hardware SPI.
  
• Lookup-table commands.
  
• Software reset.
  
• Read serial input from standard download cable (SERRXD to complement SERTXD).
  
• Swap variables without using an intermediate.
  

You can control the USB flash drive device over SPI (less timing problems), hence the 28X1 could be quite useful. You can perform SPI on lower-end devices by (slow, inefficient, large) bit-banging routines. SPI requires four lines, so the 08M won't have enough free pins to control the player over SPI. (I think, I haven't used SPI myself before).

I'll probably be getting myself a 28X2 at some point to experiment with, but I'd still suggest that you play around with writing software for an 08M hooked up to your calculator (doesn't have to be anything exotic - use the PICAXE's ADC to sample an analogue source (eg light level) over time and get the calculator to plot a graph or something). Just to get familiar with the system before splashing out on expensive parts.

[rcfreak0]

hey, thanks for the info. Im gonna read that whole wiki topic sometime soon after i do my homework. Ill work on coding for the 08M until i know i can, then ill order the 28X1/28X2 PICAXE. Ill let you know. Also, would the mp3 player be able to run off the calc battereies or no? I plan on taking it out of its case so it will fit better in the calc .

--rcfreak0

EDIT:

For your PICAXE-08/08M TI Link Functions, i dont know how to use routines. man im dumb, but seing i dont have much access to a comp right now, but when i tried them, my computer wouldnt let me do anything with the files except extract them. i dunno what to do for that part. Help?

[benryves]

They're plain text (.bas) files. You can open them in notepad, but really you should open them in the Programming Editor software. You'll need to set the software into PICAXE-08M mode, and if you open the file then press F5 it should download to the connected 08M automatically.

If you look in the manuals you should see some simple programs and tutorials (eg just flashing an LED) that should help get you started. Note that once the PICAXE-08M is running at 8MHz all communication speeds are doubled, so you need to set the Programming Editor to 8MHz too.

Look at page 17 in this manual for pinouts. You'll need to connect the 5V, 0V, serial in and serial out lines.

If you write this simple program:

[rcfreak0]

Thanks. Its probbably just my computer being stupid. Once i get ungrounded ill work it again. Im gonna read the stuff you linked me about the pinouts. Ill post more later if i have anyother questions. Oh, wait i do have another question. For the Vmusic mp3 player thing, would you be able to write some sample code for the PICAXE to run it? Also for the calc part i might need someone to code part of it, or at least get me started. Thanks again,

--rcfreak0

[benryves]

Well, I wouldn't be able to test any of the code unless I got myself one of those Vmusic devices myself (which is tempting as it is a very nice bit of kit, but I'm trying to keep spending to a minimum at the moment). This is why I'm suggesting you look into writing test programs to get familiar with the PICAXE system, as well as transferring data to and from your calculator.

Telnet 83+ and CalcSys both have link terminals, where you can send/receive data. These are both useful for testing. If you look in the MP3 player manual you can see the format for messages to be sent to control the player; using Telnet 83+ you could type in these messages on your calculator (with the PICAXE acting as a bridge to convert the TI signals to and from the serial or SPI signals) and see the responses.

Omnicalc provides raw byte sending and receiving over the link port (see here) but you'd really have to write an assembly program to communicate with the PICAXE nicely (eg sending and receiving whole strings).

If you'd find it useful, I could probably knock together an assembly library that could be used to send and receive more extensive data types (eg strings) for use in a BASIC program.

[rcfreak0]

Hey, i dont want you to have to spend any money on this, i wasnt trying to imply that. i was just wandering if you could just write something off a whim, but that was just a wonder. I have calcsys, and i like that alot. Ill download telnet83 once i get back on a computer thats not at school. As for assembly coding, IM OUT! i have issues with basic, and having to learn assambly would be bad, especially since i have restricted access to my home compute, so i dont know what an assembly library would help me with in that respect. I cant wait till i get my comp privlages back so i can start coding.
Thanks again,

--rcfreak0

EDIT:
this is the right file for Telnet83 right?

[benryves]

If you have an 83+, you'd need the 83+ version.

[rcfreak0]

close enough . Thnaks for the correction. :)

Sorry for the double post, but i have another question. What language should the calc program be in. My freind at school can code some basic (alot more than me) and if anyone else has any ideas or sample code to go off of, it would help. Or a tutorial of some kind, anything to help with the calc part. :hmpf:

Can't justify a two-minute gap between posts. Edit next time, or wait a few hours. –Weregoose

Sorry, i guess i didnt relize it was that short of a gap, sorry Weregoose, my bad.

[rcfreak0]

Update!

I am still workng on this project, but since im still grounded and im still in school, its taking awhile. The project is not dead, just moving really slow. If anyone has any ideas for a calc program that will get all the music data, let me know. Thanks again Ben for all the help so-far.

--rcfreak0

[rcfreak0]

Question.

What do i all need to complete this project.
I have an PICAXE 08M, but i dont know if that will run the VMusic player. so, my question is what PICAXE do i need to run the Vmusic? That way i can order what i all need at once.

(still grounded, and now were moving , so its still moving slow)

--rcfreak0