Latest upgrades:

2015/04/19: With great help from David Clarke, the annoying patch 51 bug is fixed among few minor ones. The rev1 release is also been tested and it's working. This looks pretty good now!

2014/07/10: The CPU upgrade project is going forward. The first prototype of CPU board is ready.

2013/01/13: Site is up again. It was hacked by some ***er. My apologies for two weeks off line time.

2012/10/28: Bug fixes: release foot switch inverts the stored release button value, 2nd lfo combined tri+saw waveform is summed wrong way. Both fixed now. The patch 51 bug is still there.

2012/06/28: ADC routine works now as I wanted, Unison1 mode has blinking led, 2nd LFO has reset on keypress and single cycle modes, PS1+PS5 toggles NVRAM viewer.

2012/05/15: Pot value display shows on PS1-PS8 leds if the pot is dialed to value stored on current patch

2012/05/11: Three month of doing nothing is over: Code is optimized and to do list is almost empty. Support for 2708 eproms is dropped.

2012/02/09: Second LFO (almost) done. Due 7bit DAC the second LFO is bit rough therefore it can't be used with VCOs but it works quite well as oscillator PW, filter and/or mixer modulator.

2012/02/08: Release foot switch code is changed: Pressing footswich inverts the state of release button. Release value and frontpanel led is turned on/off when foot switch is pressed depending if release switch is off/on.


New firmware needs 2716 eproms in order to work so minor modification is needed to perform to the synth. Here's the instructions how to modify stock rev2 to use 2716 eproms. Due the fact I dont have the rev1 Prophet, I can't give information regarding the rev1 Prophets. It's possible to use the old factory binaries burned on 2716 eprom after the modification is done.

New features are:

- Edit mode is toggled by turning any programmable pot (with black knob) or pressing programmable (black) switches. Preset button works as in stock P5 switching between manual / preset mode or return from edit mode back to preset mode (recall patch)

- Autotune is bypassed on start up. It uses previous values stored on NVRAM. Autotune does not reset the synth and it will instead return back on same state where it was before autotune. It also displays voice being tuned on preset button leds. (1-5 shows voice, led 8 indicates the voice b.) Now the P5 will boot if autotune fails to get reference count from OSC 1A. Autotune is engaged from PS1+PS4 on rev1 Prophets.

- Filter preset toggles reference A440. It tracks the keyboard (last note priority) so in can be used as monophonic DCO. It's also used for tape load as in stock P5. The ref A440 is not used on rev1 due the need of extra hardware. (Don't ask me how to do this, I still do not own the rev1.)  

- Unison button has 3 positions, off (poly) - Unison 5 - Unison 1. Mode changes on cycle. Unison mode is stored on current patch.

- Mod preset enables page 2 for (software based) 2nd LFO. When swiched on LFO speed sets the frequency and PMOD MIX sets the amplitude for second LFO. Waveform swithces and PMOD destination switches are used for waveform selection and modulation destination. FREQ1 and FREQ2 modulates the mixer OSC1 and OSC2 VCAs. PWs and FILT are routed as named. Mod Preset button is also used for tape storage.

- Edit button (or PS5+PS8 on rev1) enables setting page. Values are stored to NVRAM.
* PS1: Factory preset bank enable. Original Factory patches are stored on ROM. These are editable and can be stored to NVRAM.
* PS2: 2nd LFO enable.
* PS3: Minimoog unison keycode enable. This chooses 6.1c or 7.0 unison keycode.
* PS4: Amount of voices, 1 or 2, used on Unison 1 mode
* PS5: 2nd LFO reset on keypress enable
* PS6: 2nd LFO single cycle mode enable (kind of envelope mode)
* PS7: Disable playable ref440
* PS8: Enable pot value display (shows HEX values)

- New preset button combinations:
* PS1 + PS2 not used (was used to toggle the A440 on rev2)
* PS1 + PS3 toggles voice watch display (PS1-PS5 leds) 
* PS1 + PS5 toggles NVRAM Viewer (Unison pot selects pot and switch value offset, 0-23, for current patch. PS1-8 shows stored value. The data output is on reversed order, PS1 led is bit0, PS8 bit7.)

- Patch memory locations and tape format is compatible with the old firmware.

- Manual mode doesn't store the switch values to RAM any longer (these memory locations are used for second LFO). All switches are cleared when manual mode is entered. The manual mode can be regarded as blank canvas for new sound creation.

- Foot switch toggles the state of Release button from the programmed value.

- Pot value display shows HEX values of the pot being turned. PS1-8 leds shows if the pot is on stored patch value of direction where to turn it.


Eprom binaries are free, but now at the beta phase you can have files only by sending mail to riku() 
I want to keep some control over these beta releases and release working and complete version for public when the testing and coding is done. Reason for cathering e-mails is just for sending news about new versions and informing about possible bugs on firmware and having some sort of idea how many users there are for this.


Modified / Upgraded firmware is based on v7.0c firmware. The parts of the v7.0c, v6.1c and v5.2c code used here are probably owned by who ever owns rights to old SCI stuff.


P5r2 technical manual 2nd edition