The FV-1 DEMO board
As received from Spin Semiconductor, the FV-1 demo board should look like this:
If you don't have one of these puppies, then you will need to get one for most of the FV-1 information to make any sense. Contact your local Spin Semiconductor representative, and inquire about an FV-1 demo board. This one is #SPN1001-DEVB.
The board may be powered by either USB or an external 9VDC power supply. Sometimes the USB power (due to the grounding of the PC) can cause signal path noises that can be eliminated by powering the system from an external source. While developing programs, it is particularly convenient to convey both DSP program data and power via the USB cable only.
The right side of the board shows the FV-1 part, connected through simple passive components (coupling caps and protection resistors) to the upper four RCA jacks, allowing stereo in and stereo out, at 1V RMS levels (0dBV). A small patch area exists to the right of the FV-1 for the addition of any extra circuitry as you may wish. The 8 pin EEPROM to the left of the FV-1 can store 8 programs, and is in a socketed DIP package so that it may be removed to convey program information to a mass production programmer; alternatively, the SpinAsm project assembler can create a HEX file for this purpose.
The EEPROM is normally connected to the FV-1 through a 2 wire interface, but on the demo board it is also connected to a USB chip with its own crystal and supporting circuitry on the left side of the board. The actual circuitry required in a product consists of that which is within the white boxes, printed on the board.
Along the front of the board, from left to right, are: A switch to select whether the executed programs are to come from the FV-1 internal ROM, or the external EEPROM, an 8 position selector switch labeled 0 to 7, and three control potentiometers, labeled POT0, POT1, and POT2. These last controls are connected directly to the FV-1 and allow real time control of various programmed parameters.
The FV-1 demo board comes assembled with a 46.6084KHz crystal (cylindrical), which allows audio response to 20KHz, while limiting the total delay of the FV-1 internal RAM to 703mS. Use of a cheap 32768 watch crystal (widely available), will preserve signal bandwidth to 15KHz, and extend the internal delay memory to 1 second. The vast majority of effects applications do not suffer from a reduction in signal bandwidth, but are often improved by the extended available delay time.
Once connected to a PC that has SpinAsm installed, programs can be written and quickly downloaded for audition. Further, the SpinAsm program allows the collection of 8 programs into a 'project' that can represent the final memory image for your custom product.
The inputs and outputs of the demo board may require the use of a mixer, and of course, a sound source. The connection of the demo board to a small mixing console through its send and receive connections is advised. When developing effects that are intended to be mixed back into the original signal, a mixer is necessary.