Nottinghamshire-based 8086 Consultancy has launched a carrier board for the Raspberry Pi Pico, Pico W, Pico 2, or Pico 2 W designed for anyone who has found themselves a pin or two short on a project — the PicoIO64, which adds 64 5V-tolerant general-purpose input/output (GPIO) pins to the board.
“The PicoIO64 adds 64 3.3V I/O pins (5V tolerant) to the Raspberry Pi Pico using four 16-bit [MaxLinear] XRA1403 SPI IO expanders coupled with an 800mA 3.3V regulator,” 8086 Consultancy’s Chris Burton explains of the company’s latest board design. “The I/O can be used for front panel LED, buttons interfaces, etc.”
The PicoIO64 delivers an impressive 64 GPIO pins on any model of Raspberry Pi Pico, through a quartet of expander chips. (📷: 8086 Consultancy)
The board’s input/output pins are arranged in two banks, each of which have two 16-bit IO expanders with dedicated SPI connections, IRQ, reset, and chip select. “Splitting the banks like this,” Burton explains, “allows each bank’s SPI interface to be controlled using a dedicated core of the [Raspberry Pi] RP2040/RP2350 at up to 26MHz.”
Each of the 64 GPIO pins on the board can be configured as a push-pull output with optional three-state mode, input with optional polarity inversion and optional 100k pull-up resistor, or for what Burton describes as “a multitude of interrupt options” including rising and falling edge triggers and filters. Each pin can source or sink up to 25mA with a total of 100mA per eight-pin bank an a source limit of 160mA total across each extender’s 16 pins.
The board is available to order now on the 8086 Consultancy Tindie store for $12.50 as a self-assembly soldering kit or $16 fully assembled; a CircuitPython library for controlling the MaxLinear expanders from the Raspberry Pi Pico is available on GitHub under the permissive MIT license.
