Hi, I'm working on a project where I need to control a large number of shift register outputs updated at 44.1kHz audio rate. I built a board in the past that worked well for controlling 64 outputs (8 shift registers), I'm now working to expand it to more outputs for a different application.
To control more outputs I'm designing a daisy chainable PCB . The master PCB will have a Teensy 4.1 populated sending SPI signal to the shift registers. This PCB will send output to a series of daisy chain PCBs without the 4.1 populated using differential encoders between each PCB.
The intention for this project is to control a very large number of shift register outputs (somewhere in low thousands). To this end I'm planning to run SPI at around 100 mHZ clock speed (100mHz / 44.1kHz = ~2267) and setting up an interrupt that starts a SPI transfers via DMA at 44.1kHz sample rate.
For sending SPI between the PCBs I'm using SN65LVDS32DR and SN65LVDS31DR differential transmitter + receivers with shielded Cat6 cable. For the shift registers I'm using 74LVC595 high speed shift registers. I'm also using SN74LVC125 schmitt trigger buffers for signal cleanup on the input and output of the PCB.
Please find my schematic attached? Does this seem like a reasonable approach to the stated application? I'm trying to make this as modular as possible while using a single PCB design.
To control more outputs I'm designing a daisy chainable PCB . The master PCB will have a Teensy 4.1 populated sending SPI signal to the shift registers. This PCB will send output to a series of daisy chain PCBs without the 4.1 populated using differential encoders between each PCB.
The intention for this project is to control a very large number of shift register outputs (somewhere in low thousands). To this end I'm planning to run SPI at around 100 mHZ clock speed (100mHz / 44.1kHz = ~2267) and setting up an interrupt that starts a SPI transfers via DMA at 44.1kHz sample rate.
For sending SPI between the PCBs I'm using SN65LVDS32DR and SN65LVDS31DR differential transmitter + receivers with shielded Cat6 cable. For the shift registers I'm using 74LVC595 high speed shift registers. I'm also using SN74LVC125 schmitt trigger buffers for signal cleanup on the input and output of the PCB.
Please find my schematic attached? Does this seem like a reasonable approach to the stated application? I'm trying to make this as modular as possible while using a single PCB design.