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The circuit I'm trying to make (and eventually make PCB etc.) consists of 1 microcontroller (atmega32 , internal 8 MHz clock) sending serial data to 5 daisy chained MBI5026GF (16 bit shift register and constant current LED driver IC).

The whole board dimensions will be 15 x 15 cm (~ 6 x 6 inches) maximum. All ICs are close to each other (no long wires etc.) and contained in a sealed metal casing.

The questions are:

  1. Will I need buffers between SIPO units?
  2. If so, should all 3 lines (data, clock, latch) be buffered or just data line?
  3. Should the first inputs (MCU to first MBI5026GF) be buffered too, or just the lines between the shift register ICs?
  4. For this kind of buffering, should all buffers be non-inverting? Otherwise I'll have a hard time inverting some of my bits accordingly (second and fourth 16 bits) before sending them over serial output, right?

I'm trying to replicate this common 74hc595 circuit, but with 5 registers, and of course all replaced by 16bit ones (mbi5026gf):

Daisy chain diagram [Image from hackster.io]

This shift register is very similar to 74xx595, so your experiences and answers for 595s can be useful here as well.

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  • \$\begingroup\$ You will need to provide links to the manufacturer's datasheets for the shift register and also for the microcontroller. Tell us about the frequency and timing relationship of the data, clock, and latch signals. Ideally, you would provide a schematic to show how you plan to connect the shift registers if you don't use buffers. \$\endgroup\$ Apr 4, 2021 at 21:41
  • \$\begingroup\$ @elliot Alderson, edited the question \$\endgroup\$ Apr 4, 2021 at 22:00

1 Answer 1

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No, nothing in the datasheet indicates that it needs buffering.

It will work just fine if connected to any MCU with 5V IO voltages.

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