Speech256/boards/Digilent DE0/README.md

Digilent DE0 board

• Altera EP3C16F484C6 FPGA

The DAC output is the UART_TX pin. It really needs a 5kHz lowpass filter, otherwise you'll be deafened/greeted by a very loud 10kHz PWM carrier. Try a 330 ohm series resistor, followed by a 100nF capacitor to ground:

UART_TX pin ----RRRRR---------o OUTPUT
                           |
                           C
                           C
                           C
                           |
                          GND