Attached are two projects (full version and the stripped one) demonstrating DMA transfer from the ADC_SAR to the Filter component and then to the VDAC8 (for testing purposes). This should help you going. The project shows essential ADC, DMA and Filter settings and helps to understand the capabilities and limitations. The ADC sampling frequency is set to 48kHz, and Filter cut-off is set to 5kHz to demonstrate filtering technique. Project uses CY8CKIT-059 Prototyping Kit.
The full version of the project includes a signal generator, which frequency can be varied using simple rotary encoder. The DDS32 and WaveGen8 are already included in the project. You can download other community components from the Community space:
The stripped version of the project has no any custom components, but requires external signal (sine) generator as a source.
Neither version shows how to DMA from the Filter to the SPDIF component, but let's leave it for the later. To test and debug SPDIF version you will need a receiver (SPDIF to Analog).
Figure 1. Project schematic.
Figure 2. Output signal testing using VDAC.
Figure 3. Optional signal generator using DDS32 and WaveGen8 custom components (full version only)
Figure 4. Project annotation (full version) using PSoC Annotation Library v1.0
Figure 5. Project annotation (stripped version), which has signal generator stripped out.
Figure 6. Blue trace - 1 kHz, 4Vp-p signal input. Yellow trace - signal output. Magenta - sine reference. Notice that output signal amplitude is 4 times less that the original input signal, and is not centered around Vdda/2 as expected due to the ADC_SAR internal bug. Some solutions are possible to remedy this (later).
I added extended versions of the ADC_SAR-Filter-VDAC demo using DMA in Community Code section
It shows couple of ways to resolve ADC_SAR issues of low output signal amplitude. To achieve SPDIF output you would need to replace output source from VDAC8 to SPDIF component.
Hello! Had a busy week, sorry for the late response. Thank you very much. I'll have a look into it this weekend.
Actually my PCBs with analog frontend and SPDIF transceiver have arrived this week, so there will be some hands-on experience soon.
I'll keep you posted.