MCP23017 Went Through Shortage Hell, Lost Two Inputs

Showing two MCP23017 expanders soldered onto a PCB

The MCP23017, a 16-bit I2C GPIO expander, has always been a tasty chip. With 16 GPIOs addressable over I2C, proper push/pull outputs, software-enabled pull-ups, eight addresses, maskable interrupts for all …read more Continue reading MCP23017 Went Through Shortage Hell, Lost Two Inputs

Being a SPI Slave Can Be Trickier than it Appears

Interfacing with the outside world is a fairly common microcontroller task. Outside of certain use cases microcontrollers are arguably primarily useful because of how easily they can interface with other devices. If we just wanted to read and write some data we wouldn’t have gotten that Arduino! But some tasks are more common than others; for instance we’re used to being on the master side of the interface equation, not the slave side. (That’s the job for the TI engineer who designed the temperature sensor, right?) As [Pat] discovered when mocking out a missing SPI GPIO extender, sometimes playing the …read more

Continue reading Being a SPI Slave Can Be Trickier than it Appears