TDGmaker

I know, so today I changed the 8 MHz processor and crystal for a 20 MHz type (16 MHz for mega8535). I slipped in some more delay routines, played with the timing and now, everything is running smoothly! This way it can perform some more tasks, like LFO's and LCDs and such.

It's fixed! The problem was that the timing between pushing bits towards the 74hc595 and clockin them in. Thanks for pushing me in the right direction! I'll include my routine here, for others to freely use and ofcourse, make it better! Sendportc: SendportcSetup: ldi temp,16 sts shiftcount,temp lds temp,portcout ;keep CS low cbr temp,CS ; sts portcout,temp ; out portc,temp lds temp,shiftctrl ;keep RESET high sbr temp,sidreset ; sts shiftctrl,temp ; sendportlus: lds temp,portcout cbr temp,RCLK ;dont show outputs 74hc595 cbr temp,SCLK ;clockbit low sts portcout,temp out portc,temp sendcrotate: lds temp,shiftctrl clc ror temp ;shiftctrl to right sts shiftctrl,temp lds temp,shiftdata ror temp ;shiftdata to right sts shiftdata,temp brcs sendwelcarry ;carry set? sendgeencarry: lds temp,portcout cbr temp,serdat ;put 0 in serdat sts portcout,temp rjmp sendport sendwelcarry: lds temp,portcout sbr temp,serdat ;put 1 in serdat sts portcout,temp sendport: lds temp,portcout out portc,temp ;out with the serdat bit ldi temp,0x20 ;delay senddelay: ; dec temp ; brne senddelay ; lds temp,portcout sbr temp,sclk ;clockin high sts portcout,temp out portc,temp lds temp,portcout cbr temp,sclk ;clockin low sts portcout,temp out portc,temp lds temp,shiftcount ;all 16 bits done? dec temp sts shiftcount,temp brne sendportlus ;nope SendportcShow: lds temp,portcout sbr temp,CS ;CS high sts portcout,temp out portc,temp lds temp,portcout ;RCLK high sbr temp,RCLK sts portcout,temp out portc,temp lds temp,portcout ;RCLK low cbr temp,RCLK sts portcout,temp out portc,temp lds temp,portcout cbr temp,CS ;CS low sts portcout,temp out portc,temp SendPortcEnd: ret

The mega 8535 is not overclocked, it is running at its own normal speed (being 8 MHz coming from a crystal). Your hint for the timing between setting the serial input and settings of SCLK=1 sounds like a good idea. I'll be happy to show you the code of my routine that sends the data to the 74hc595's. (come to think of it; i already tried building in a delay but that didn't work out, never thought of the NOP's though.. good idea!) In my routine i use two databytes for controlling the SID. 1: shiftctrl = holds the addressreg for the data 2: shiftdata= holds the data for that address And one more: 3: portcout = contains the data that will be put on the port (i do this so i can alter the bits without disturbing any real outputs on portc, this way only the correct byte appears on the port C) Reset bit is being set in the routine here below, as well as the controls for sending the bits to the 74hc595s Hope you can read it well.. Sendportc: SendportcSetup: ldi temp,16 sts shiftcount,temp lds temp,portcout ;keep CS low cbr temp,CS ; sts portcout,temp ; lds temp,shiftctrl ;keep reset high on SID sbr temp,sidreset ; sts shiftctrl,temp ; sendportlus: lds temp,portcout cbr temp,RCLK ;outputs 74hc595 low, do not show cbr temp,SCLK ;SCLK clockbit keep it low sts portcout,temp out portc,temp sendcrotate: lds temp,shiftctrl clc ror temp ;shift first ctrlbyte sts shiftctrl,temp lds temp,shiftdata ror temp ;shift second databyte sts shiftdata,temp brcs sendwelcarry ;carry set? sendgeencarry: lds temp,portcout cbr temp,serdat sts portcout,temp rjmp sendport sendwelcarry: lds temp,portcout sbr temp,serdat sts portcout,temp sendport: lds temp,portcout out portc,temp ;portcout op port C zetten lds temp,portcout sbr temp,sclk ;SLCK clock high sts portcout,temp out portc,temp lds temp,portcout cbr temp,sclk ;SLCK clock low sts portcout,temp out portc,temp lds temp,shiftcount ;clkcounter test all 16 bits dec temp sts shiftcount,temp brne sendportlus ; ;rjmp sendportcshow SendportcShow: lds temp,portcout ;RCLK high, show the outputs.... sbr temp,RCLK sts portcout,temp out portc,temp lds temp,portcout ;RCLK low cbr temp,RCLK sts portcout,temp out portc,temp SendPortcEnd: ret EDIT: I've noticed I've never actually made CS low on the port nor do I make it high in the routine..hmmm I'll try to make CS high, show on port then transfer bits to 74 hc595 make CS low, show on port and show bits 74hc595 to SID And insert a few NOP here and there..

I actually also did run the SID asynchrone with an AT90S8515. And that ran perfectly, SID directly connected to the 8515. Now, 2 years later, i decided to use the SIDboards you designed in combination with a mega8535 (for obvious reasons, being the onboard 8x ad conversion etc..). Earlier on i had trouble issues with the powersupply of this newly build SIDsynth, but this has been overcome. It puzzles me why this new combination did not work as well as my old setup. So I suspected it had to be something with clock not being sync. (although I've never had any troubles with that before...). As is said; the board for the SID is now a board you designed (v3). My only change is that the CLK input is being fed by a crystal of 1 MHz and not by a PWM output. Outside that board is a mega8535 with a midi in- and output. (you might want to have a look at http://avr.tjerkdegroot.nl/) Also i completely reprogrammed the routine, it now only has the basics to trigger notes etc. Your last post made me start thinking about the CS# en WE# lines... I'll check them, first thing.. The CS is connected to the SID via a pin on the 8535, directly to the SID. The WE (I guess the R/W line is what you mean) is connected directly to GND via your board. The RES (reset pin no 5 on SID) is connected to a pin on the 74hc595 Seems ok to me? Thanks for your cooperative support Thorsten!

It doesn't sound like that, thats more a phasing-like problem. Mine is really like bits are not read correctly due to the async of the clocks. All 3 oscillators are with the same pitch, the result that is computed is correct and also correct on the output pins of the 74hc595's. The result in sound are wrong, some are off pitch, others on pitch. Every time a note is played on the SID the result is different. It seems like some bits are not read correctly by the SID, all the pins on the 74hc595's are correct though. So that made me jump to the conclusion that it might be the 1 MHz clock being async with the mega8535.

That's exactly what i mean. I've checked what my mega8535 made of the midi codes for the SID and they were all correct and the same every time. So the only factor that could make the difference is the fact that the SID and the mega8535 are running asynchrone.

Mine is working also, but the notes are not sounding equal every time. My guess this has to do with the crystal not being in sync with the crystal of the atmel. How did you make the clock tick with the SID? I guess a possible solution would be to make a timer pwm output run at 1 MHz. Any suggestions??