The CT3680 V1 Development Board is an aid in prototyping and development of CT3680 V1 based products. The dev board makes all the inputs and outputs of the module accessible through header pins and connectors. The board has 6 potentiometers for manual CV control and switches for setting the program number and option inputs. Audio inputs and outputs are available through standard TS (mono) 3.5mm jacks, as well as a TRS (stereo) connector that combines audio outputs 3 and 4. The dev board also has probe points for all 40 pins of the module as well as headers for signals that may be processed off-board.
Development Board Features
The power section of the board has a 2.1mm power jack (center positive) for +5V power input, an ON/OFF switch, and a LED. The ON/OFF switch allows control of power to the module without removing and inserting the power plug. The power indicator LED lights when the module is powered (as a reminder not to insert or remove the module while the power is ON).
Double header pins are supplied for off-board access to 5V, 3.3V, and GND. When using multiple development boards (linking modules) it is handy to jumper the 5V supply and GND lines together so only one board needs to have a power plug. Do not tie 3.3V supplies of multiple boards together. Each board generates its own independent 3.3V supply via a regulator on the module.
Program Selection
The board has 4 program selection switches to allow setting the program without installing or removing jumpers on the module itself. The program select lines are also made available on header pins so program selection can be controlled off-board (for example, by a microcontroller). When driving the program select lines off-board, the switches must remain in the LOW (off) position.
Option Selection
The board has 4 selection switches in the OPTIONS section that allow control of various program options. Header pins make option control available to an off-board controller. When driving the option pins off-board, the option switches must remain in the HI position.
Delay (CV) Controls
The board has 6 potentiometers along the bottom edge for control of the min/max/1/2/3/4 delay parameters. At the full counterclockwise position, the CV voltage will be 0.0V, full clockwise is 3.3V. The potentiometers are linear. If CV is to be supplied off-board, the CV control jumpers should be removed, and the external CV signals should be supplied to the upper pins of the jumper block (closest to the CT3680 module). When driving the CV controls from off-board, the CV jumpers must be removed. The jumper block also contains GND and 3.3V pins for off-board reference. Be sure not to install a jumper across the GND/3.3V pins.
Audio Input/Output
3.5mm TS mono jacks are provided for the (4) audio input and (4) audio outputs of the CT3680 module. Each input and output also have a single header pin that is handy for clipping test leads to. There is also a single TRS stereo output jack that combines audio outputs 3/4 into a left/right stereo pair.
Multi-Module Linking
The board has two headers in the LINK section for linking modules as described in the Chaining Multiple Modules section of the datasheet. Each header has 4 pins. The primary module development board should have its “DN” (downstream) header connected to the secondary module board’s “UP” (upstream) header. Connect all 4 pins of the header from one board to the next (e.g. pin 1 upstream to pin 1 downstream, pin 2 upstream to pin 2 downstream, etc). If a secondary board is to be connected to another secondary board, connect its DN header to the next board’s UP header, and so on, down the chain of boards.
For secondary module boards, the switch in the LINK section can be set to “1 CH” for single channel linking, or “2 CH” for dual channel linking.