For many modern and powerful chips like the RP2040, ESP32, RT10xx, and STM32 series microcontrollers, designers can save money and reduce the number of chip options by not including building in the Flash memory used to store code and resources. Instead, an external QSPI Flash memory chip is wired up that can provide up to 16 Megabytes (a.k.a 128 Megabits) of memory. It's not as fast as if it were on the microcontroller internal bus but with Quad SPI I/O and some clever caching by the chip designer, it's pretty effective!To make prototyping and designing with QSPI flash a...