SwinSID Ultimate is suitable for:
- Commodore 64 and 64C
- Commodore 128 and 128D
- Commodore Max Machine (Ultimax/VC10)
- Commodore CBM II series
- Commodore 64 Reloaded MK1 and MK2
- Ultimate 64
- many C64 stereo SID cards
- BeepSID (for BBC Micro)
- SID Card (for Plus/4)
- PlaySoniq (for MSX)
- Hard SID
- Catweasel MK3, MK4 and MK4plus
- Innovation SSI 2001 (PC sound card)
- The Entertainer (PC sound card)
- SIDblaster
- SID Station
- HyperSID
- Mode Machine SID
- MIDIbox SID
- SID GUTS/SID GUTS DELUXE
- and other
Full feature compatibility with the original SID:
- paddle/mouse support
- readable registers (OSC3/ENV3)
- external audio in
- bitfade
- proper ADSR-bug support
- fast ADSR attack rate (thanks to the self-correcting rate-counter)
- “Lazy Jones” and “180” -like gate and test-bit workaround (no missing note)
- proper 23 bit noise-waveform calculation for better “random” numbers
- full 3 V p-p output range w/o 1 KOhm load (same as 8580)
- improved filter quality (16 bit) and resonance-table for both SID models
- improved waveform calculation (full 16 bit)
- high resolution combined waveform-tables
Enhancements over the original SID:
- clean anti-aliased bandlimited sound at high pitches
- undistorted mixed digi tunes and eliminated volume-change click thanks to AC/DC separation of master volume register
- Softconfig—software configurable options for a number of aspects of the operation
- LEDs which intensity represents the active channels volume
- LED displaying the active (classic) digi playback
- or in case of the new Mahoney-digi, the entire array acts like a VU-meter
Configurator
A Commodore 64 program for configuration can be found here:
SwinSID Ultimate Configurator
User's Manual
Credits
Base work: Swinkels
Feature enhancements: CodeKiller, Hermit
Quality improvements: Hermit, CodeKiller
Manual written by: CodeKiller
Introduction
SwinSID Ultimate is a HIGHLY ENHANCED version of the original SwinSID design by Swinkels; so much so, that almost the entire code has been rewritten. Due to wast differences in 6581 sound, this project aimed to be more like the 8580 (with digi boost), but also has support for 6581-like characteristic* (see later)
Technical Details
This module is the same form factor as the original SID (DIP 28) but does not utilise all pins the same way. In the place of the pins for the filter capacitor connectors there are two jumpers (+ marks the default/recommended position) :
PIN1-2 - CLOSE +: normal operation (no programming) / OPEN: atmega88 can be reprogrammed (by default, the program is protected against reading)
PIN2-3 - OPEN +: normal output volume / CLOSE: reduced output volume (in some rare cases it may needed if paired up in dual SID)
The +9/+12V supply is not needed:
PIN28 (Vdd) - not connected
PIN27 (Audio out) - because the sound generation uses phase-correct PWM outputs, theres is a ~72,7 kHz carrier at any time with filtering it's amplitude has been reduced but still can be detected also, because the module powered from only 5 V the output level may be lower than of a normal SID it is advised if you put it in place of a 6581, remove/disconnect the 1K resistor pulling the output to the ground recommended in place of 6581:
S |
I |
D |
27|-----*---.....
| X <--- disconnect/remove
| '--\/\/\-----,
1k |
---
PIN26 (Ext in) - it's not an analog mixing anymore, but goes digital trough an ADC, so can be read/record data by the computer but because of the construction of the input stage in a C64, there can be a lot of noise coming in if switched on a termination resistor (for ex 1K) recommended before the AC-coupling capacitor recommended if ext in required:
S |
I |
D |
26|---------||----*---< ext audio in
| |
| '--\/\/\-----,
1k |
---
Sound Generator
Voice generators:
To simulate the SID chip, the module generates 3 separate voices and a "classic digi" channel in with the master volume bits. These waveforms are calculated in 16bit resolution before adjusting the volume and mixing to the output.
The 6581 compatibility had been greatly improved with the proper ADSR envelope and mixed waveform adjustments beyond the differences of the filter characteristic.
The module has it's own clock source so to generate the proper pitch it has to be set to proper mode. It can be changed by SoftConfig commands.
Over the regular waveforms there is a possibility to upload three 256 byte long custom sample in place of 3 mixed waveform selectable by the control register byte 0x9*, 0xA*, and 0xB*.
These custom waveforms are responding to the input frequencies the same way as the regular waveforms.
In case of a Mahoney-digi condition has been detected, the module switches to an alternative execution route and reads the desired output levels from a data-table.
Selectable operation modes: PAL / NTSC
Base clock for PAL: 985248 Hz
Base clock for NTSC: 1022727 Hz
Calculation resolution: 16 bit
Output Stage:
The sound output is generated by two phase-correct PWM sources combined.
The carrier signal is a triangle waveform.
The output range has been optimised for the timing restriction too.
The output stage is a dual-PWM combiner with a ratio of 220:1
The lowest response (input register to sound output): 1/36363 =27,5 uSec
DAC resolution: ~15.5 bit (220*220)
Carrier frequency: 32 MHz/220/2= ~72.7 kHz
Sample rate: ~36.3 kHz
Signal-to-Carrier ratio >20 dB (can be improved with further LPFs)
LEDs
This module features an array of 4 LEDs to display informations about the sounds.
Note mode:
By default, the first 3 LEDs' intensity represents the 3 voice's volume (current ADSR envelope). The 4th LED displays if a classic digi has been playing (the 4 bit of master volume). If the Mahoney-digi condition has been detected, the LEDs act like a VU-meter, displaying the master output level.
RW mode:
In this mode, only the first 2 LEDs working to indicate the register writes and reads. This mode is real-time, so the brightness could be really faint.
Inverse note mode:
Due to the LEDs are driven by the CPLD, the sourcing current is much lower than what it could sink. So if the LEDs has been added/changed, in this mode it can produce higher brightness. But it's highly recommended to use some proper LED-driver circuit if you need brighter/bigger light output! In that case, the driving polarity can be changed to match the requirements of the driver circuit.
ADC input
Ext in:
The external audio input is mixed in to the output digitally after an ADC stage. Therefore it is possible to enable/disable it or if enabled, then record the values by the host. (If the Mahoney-digi condition has been detected, the ext in audio not processed, not mixed to the master output.)
Maximal volume range: 5 V AC (peek-to-peek)
Input offset: 2.5 V (use AC-coupling capacitor)
Maximal sample rate: 36.3 kHz
Working resolution: ~8 bits
POTx/y:
Electrically works the same as the original SID - samples the input and compares it to Vcc/2. It uses it's own clock source. The result of the conversion is available after some data transfer. Resetting the module does not resets the comparator's counters.
Capacitor charging time: 256 uS
Capacitor discharge time: 256 uS
Data acquiring delay: ~7 uS (during discharge phase)
Vref= 2.3 V
Discharge current: ~30 mA
Addressing
Write to registers:
Although the proper edge-based register writing can't be handled, with a sufficient precharge time and stable signal the module can operate indistinguishable to an original SID.
After the write conditions met ( PHI2(CLK) low, R/W high, CS low ), the module starts an interrupt in there it reads the address lines, then the data lines.
Taddr_pre_min - Write condition to address valid: ~170 nS
Taddr_hold - Recommended address valid time: ~150 nS
Tdata_pre_min - Write condition to address valid: ~200 nS
Tdata_hold - Recommended data valid time: ~150 nS
Twrt_cnst_min - Time between consecutive writes: ~700-1000 nS
(please make sure the write conditions does not "flicker")
Reading from registers:
Reading the registers however works as expected, valid on the falling edge of the clock. OSC3/ENV3 register values updated only once per sample-cycle.
Maximal read response time: <100 nS (read condition to data valid)
Maximal data response time: 28 uS (internal data OSC3/ENV3 change to register value)
SID model auto-detection
There has been a few codes aimed to detect the SID type in the C64. These relying on a small timing difference between the 8580 and 6581. But because this SwinSID can not respond in cycle-exact way, these codes would (usually) thake the 'else' route that means detected as 8580.
Be aware: even if the module set to 6581 mode, these programs will still detect as 8580 which could cause distorted sound!
Normal operation of the module
Normal operation of the module is same as MOS 6581/8580. Please refer to the manuals and the tutorials by the C64 community.
Special operation of the module
This module features non volatile software-configurable switches and custom waveform options in RAM.
To access these features the remaining, originally unused addresses has been reused.
Because these addresses are normally not concerned by the SID chip, extra care has been made to reduce the accidental changes.
There are two sets of command:
- information from the module (SI*): reading identifications or current states for the switches
- editing the configuration (SE*): changing the switches or other behavior of the module
In order to make it less obscure, the codes are mostly 3 byte words where the ASCII code of the letter has to been sent.
The "words" below represents the bytes needed to enter in to ascending addresses
For example:
Sending COMMAND:
poke sidaddr+29, asc("S")
poke sidaddr+30, asc("I")
poke sidaddr+31, asc("D")
The order of the rows are not important UNLESS directly stated OTHERWISE!
(as long the adresses are correct, the following works just the same:
poke sidaddr+29, asc("S")
poke sidaddr+31, asc("D")
poke sidaddr+30, asc("I")
or
poke sidaddr+30, asc("I")
poke sidaddr+31, asc("D")
poke sidaddr+29, asc("S")
)
Then reading the module's RESPONSE:
print chr$(peek(sidaddr+27));chr$(peek(sidaddr+28))
> SW
Most commands has RESPONSE bytes, acknowledging the command has been successfully processed and shows the actual state/information.
In normal operation the OSC3/ENV3 registers updated regularly, so in order to these responses be readable - The SwinSID stays in SoftConfig mode until
- hard reset: reset pin on the module goes to 0V
- soft reset (reinit): sending the command "SET"
- setting the sidaddr+29 to anything other than "S": this keeps the RAM intact!
Special cases:
- exiting 'RAM wave upload mode': sidaddr+29 = 0
- entering 'ext in sample record' returns to normal operation
- exiting 'ext in sample record' returns to normal operation
- reinit after clears the RAM and restarts the main chip returns to normal operation
Exiting the softtconfig does not provide response, also commands that automatically exits from softconfig neither. Session only changes are only preserved till the next reset! All other changes are stored in non volatile EEPROM.
softconfig commands
|||
||| names, description / RESPONSES (responses are the capital letters == CHR$() )
VVV VVVVVVVVVV
softconfig:
********************************************************
SI* (softconfig Information)
----
SID ____ SW (identification)
SIE ____ IN (identification)
SIF ____ function as: 65(81) / 85(80)
SIL ____ led config: RW-NoTe-Inv_Note
SIV ____ version: $.$ (chr$ characters)
SIA ____ audio in status: ON / OFf
SIC ____ clock config: PaL-NtSc(-2M todo)
SIB ____ start beep mode: ENabled / DiSabled
SIM ____ Mute bit-mask % (binary value 0-15) (M %)
********************************************************
SE* (softconfig Eprom Edit) response bytes after #
---- (+ = default setting)
SE6 ____ 6581 behaviour #65
SE8 ____ 8580 behaviour #85 +
SEA ____ allow audio in #ON
SED ____ disable audio in #OF +
SEE __!!!SESSION ONLY!!!__ valid only for the next reset or reinit
ext in sample recording (8bit ADC @ 36.3kHz)
after SEA, it produces:
data in OSC3 (8bit signed!)
!!!no response!!! auto-exits softconfig !!!
SEF ____ sampling Finished --- reverts back to normal
!!!no response!!! auto-exits softconfig !!!
SEW ____ custom wave input init #RY
enters RAM wave upload mode !!!session only!!! reset/reinit clears data!!!
to fill the three 256 byte wave-table not used/usable by original SID models
addr+29: wave-table select
0: upload finished/return to normal operation
1-3: selecting desired custom wave storage for wave 0x9 / 0xA / 0xB
4-255: keep in loop, waiting for value below 4
addr+30: destination position in the custom wave
addr+31: destination value to the position
SER ____ led in RW mode #RW
SEN ____ led in note mode #NT +
SEI ____ led in inv note mode #IN
SES ____ ntSc pitch #NS
SEL ____ paL pitch #PL +
SEB ____ start Beep enable #BE +
SEM ____ start beep Mute (disabled) #BD
SET ____ chip reiniT
!!!no response!!! auto-exits softconfig !!!
!!!!!!! set the parameter (addr+31) BEFORE the "M" (addr+30) or "S" (addr+29)!!!!!
SM% ____ mute selected channel bit-mask 1=mute / 0=normal @ bit3=digi, bit2=osc3, bit1=osc2, bit0=osc1 #M% (same as with SIM )
(for exampe parameter=0x05 mute voice3 and voice1 but not voice2 nor classic digi)
(the Mahoney-digi can't be muted)
Extrnal audio input/sampling:
The extenal audio input featured in original SID models too, but because this module catches more noise if not termianted properly it is disabled by default. But if handled with care it can be used all the time, no problem.
The samppling however is not only special to this module, but overrides normal operation of the SID.
So it can only changed in a volatile way to not interfering with normal operation in different scenarios (or at least a reset can bring it back to a valid SID-compatible state).
Sampling can be switched on only after the external audio input has been enabled.
Custom waveforms:
Custom waveforms are 256 byte long data that can be uploaded to the RAM and can be accessed instead of
noise+triangle 0x9*
noise+saw 0xA*
noise+saw+triangle 0xB*waveforms.
select by [sidaddr+29]
|
V 00 01 02 03 04 05 fc fd fe ff <-- position/offset/pointer/address selected by [siaddr+30]
c_wawe 1 >xx xx xx xx xx xx ...... xx xx xx xx <-- data entered from [sidaddr+31]
c_wave 2 >xx xx xx xx xx xx ...... xx xx xx xx
c_wave 3 >xx xx xx xx xx xx ...... xx xx xx xx
All 3 voices can access any 3 custom wave (obviously only one wave per voice at any moment, mixing with existing waveforms or with custom waves are not possible).
Pitch (frequency), ADSR, filter, master volume supported (PWM not)
Recommended filling sequence:
(while wave-table select is invalid -- "S" remains after entering custom wave mode)
set position beginning [or end]
set value
select wave-table
while position is not end [or beginning]
set position+= [or -=] 1
set value
Data loading is not synchronous!
It's not predictable when the entered values takes effect.
But due to very short loop, expect all value to be evaluated faster than you can send them! (Changing the address causes the value at the new address to be overwritten by the old value.)
for example:
Start
-----
sidaddr+29=1 =wave-table select
sidaddr+30=0 =postition
sidaddr+31=10 =value
c_wave1:
addr: 00 01 02 03 ....
data: 10 xx xx xx ....
position+=1
-----------
c_wave1:
addr: 00 01 02 03 ....
data: 10 10 xx xx ....
value=30
--------
c_wave1:
addr: 00 01 02 03 ....
data: 10 30 xx xx ....
Document rev. 1.1c
