Tiny Tapeout > Tiny Tapeout Chips > Tiny Tapeout IHP 26a > 843 Discrete-to-ASIC Delta-Sigma Acquisition System
843 Discrete-to-ASIC Delta-Sigma Acquisition System
843 : Discrete-to-ASIC Delta-Sigma Acquisition System
- Author: YU ICHI
- Description: A 3rd order CIC filter for PDM signal processing.
- GitHub repository
- Open in 3D viewer
- Clock: 2048000 Hz
How it works
Input 1-bit PDM signal from an external discrete 2nd-order Delta-Sigma Modulator. This ASIC implements a 3rd-order CIC filter (Decimation Ratio = 32) to demodulate the PDM signal into 8-bit PCM audio data. The design focuses on Hardware-in-the-Loop verification between a custom PCB and the ASIC.
How to test
- Stimulus: Generate a 10kHz Sine wave using Digilent Analog Discovery (Wavegen) and input it to the external PCB.
- Connection: Connect the PCB output to
ui_in[0]. - Clock: Synchronize the PCB clock with the ASIC clock (2.048 MHz).
- Observation: Monitor
uo_out[7:0]with a Logic Analyzer. The reconstructed waveform should match the input sine wave.
External hardware
- Custom PCB (Discrete 2nd-order Delta-Sigma Modulator)
- Digilent Analog Discovery 2/3 (Wavegen & Logic Analyzer)
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | PDM Input (d_in) | PCM Output Bit 7 (MSB) | NC |
| 1 | NC | PCM Output Bit 6 | NC |
| 2 | NC | PCM Output Bit 5 | NC |
| 3 | NC | PCM Output Bit 4 | NC |
| 4 | NC | PCM Output Bit 3 | NC |
| 5 | NC | PCM Output Bit 2 | NC |
| 6 | NC | PCM Output Bit 1 | NC |
| 7 | NC | PCM Output Bit 0 (LSB) | NC |