[sdiy] More details on FPGA board

[Eric Brombaugh]

I was looking through the user guide for the Spartan 3E Starter kit we 
discussed a few weeks back and happened to spot a reference to DACs and 
ADCs. It turns out that there is built-in analog I/O:

1x LTC2624
    Quad 12-bit SPI DAC
    50MHz max clk rate
    7us settling time (140 kHz rail-rail swing with < 1LSB error)

1x LTC6912
    Dual SPI controlled PGA
    1,2,5,10,20,50 gains
    (hooked up to drive 2-channel ADC below)

1x LTC1407A-1
    2-channel 14-bit SPI ADC
    3 Msps throughput (1.5MHz sample rate per channel)
    Separate S/H on each channel for simulataneous sampling.

All these connect to a pair of 6-pin 0.1" headers with power, ground and 
reference voltages available.

It seems that using this board for synth applications would be a lot 
easier than previously suspected.

Eric