I've had a look at the inside of this pedal, I can see an Spin FV-1 chip in it. However, there are 2 x 24LC32As in there. They are both connected to the same select bus (i.e. A0, A1 and A2 are all grounded).
Anyone know how it utilises both the EEPROMs? simultaneously?
Also how did they have a pot at the back of the pedal to control the swirl amount?
Are you 100% sure about the select bus? Seems to me that there is no way to address them individually...
They could both be connected to the same bus, that's fine. The pedal would need to use the chip select pins on the two EEPROMs to determine which one gets read. That wouldn't be too hard. As far as I know, the FV-1 only reads the EEPROM when the program changes, so by having two EEPROMs and selecting between them, you'd get 16 programs (EchoRec actually uses 12). As far as the FV-1 knows, it is only connected to one EEPROM. What it doesn't know is that the identity of the one EEPROM keeps changing!
They have used a different way of selecting EEPROMS, the obvious way would be to use the address lines of the IC's. Catalinbread have opted to switch chips by using fets to switch the SDA pin between which EEPROM is selected.