PROPHET64 & MSSIAH Userforum

This is clearly interesting. I'm growing tired of using disks..

But I think it's a bit too advanced for me to build . I wonder if 8bit Ventures are interested in manufacturing this device..?

thanks for ur reply firestarter, im gonna look forward to try assemble this thing..... it really deserves to give a shot, smells amazing

Hi firestarter!

I´m finished with my sdr device, or hm maybe not

It starts up just fine, checking the slots , etc. The buttons works fine , the encoder Save/Load Yes & No etc.

BUT..... When i choose save+yes i get "waiting" , so far so good i guess, but then the mssiah tells me to press space and the mssiah´s raster lines appears for a few seconds and i got "saving ready". The thing is that the display doesn´t show the saving graphics like in your video, i just got the word "waiting".

I`t freezes in that mode untill i resets the computer OR choose LOAD then the "saving" appears for half a second then "bit error". It´s like the card doesn´t get any "save output" from the serialport, the Load command does however.

I guess the loading function could work but i dont have anything to load so.......

Have i missed something, i`ve checked the board like 10 times already connections, soldering, powersupply etc.

Could it be something with the clock? the crystal? In the scheme their are two capacitors for each leg on the crystal right?

Or could it be that i´m using an SD "ULTRA" 2gb , istead of an "regular" SD card (shouldn`t be any problem it´s practically the same card)

Any tips , i´m going slightly mad here

I´m using a regular size sd cardholder , the soldering pins are a bit different, but i checked it, it should be fine.

Last edited by nusse (2012-05-07 17:45:13)

Oh hey nusse,

sorry for the late reply!
1st, it is not a capacity problem with the crystal, because else the software wouldn't run.
2nd the SD card shouldn't be an issue either becuase it scans for the slots so i guess it works. ( it might stop here already while scanning...) Most microSD or SD cards should work ( <= 2GB i guess since 4gb is another standard (SDHC) and i didn't test those yet)

I sent you a testfile for loading, so we can find out if parts of the SDR device work.

Thomas

Hey nusse,

thats weird. I can only think of the connection to the userport. There could be a problem with mirroring. For example using pin 9 instead of pin 4..
I can offer you to check it myself if you send me the device.
Let me know,

cheers
Thomas firestARTer aka Frau Holle

Oh no, don't just swap the pins. Just double tripple quadrupple check if they are right.
Wrong placed pins can hurt your C64 or the PIC microcontroller.

Only change them if you find out that they are wrong1

cheers

Hello firestarter !

I found this info here on the forum:

"The SDR (Serial Data Register) is using a built in feature of the C64's
CIA chip never used in any of its hardware peripherals nor operating
system routines. It is a simple synchronous data bit shifter that inputs
and outputs one byte at a time on the user port with two separate lines,
one for the clock and one for the data. Pins used are: PIN4 = CLK for
input PIN5 = DATA for input PIN6 = CLK for output PIN7 = DATA for output.

Is this information regarding the pins correct for your schematics?

Yesterday i tried to load your testfile, and when i pressed "Loading yes" (and the x marks started to tick) the pins 4 and 5 goes from 0 volt to something like 1.5.-1.8 volt (approx.) Do you think this is correct? The raster line dont´t appear on the screen at all just a the blue screen until i press runstop, in save mode it´s the other way around (as said before) the raster line do appear but the device locks in waiting.

In save mode i discover that if i leave the device in "waiting" mode and switch to load and press yes the "saving" and the marker appears for like a split second and then the "bit error" appears, so some kind of signal does apparently come out from the userport. This "fenomenon" also appears if i but the multimeter on PIN 1 (ground) and PIN 7 (data out).

One could suspect some mixed up line like DO v/s DI on the sd cardholder or something but i can´t really find something wrong.

I had a similar problem with the the clock/pulse signal in my sync24-64 adapter, it doesn´t worked at all. The solution the was to put a 10k resistor between ground and the clock.
Then the sync/clock worked perfectly with my Roland - 707 and mssiah/prophet 64. Maybe i should try this on the clock from the userport here as well.

One last question: Does the HI-LO settings when saving makes any difference i´ve put it in HI as in your video, but i also tried to put in the lower modes as well with no sucess.

Thanks again for your help firestarter

great. me and also a friend of mine have the same problem.
looking forward to hter new schematic

nice thanks!

one question though:
shouldn't it be possible to invert the signals from rb6 and rb7 in the firmware?

cheers Paul

of course... i totally forgot, the pic runs on 3.3v -  sorry.
i won't have a chance the try this untill at least sunday though.

i'll report back, when i get to build it.

Looks very nice full assembled!

Have fun with it!

finally managed to build it, too.
works like a charm now.

thanks a lot, firestarter!