Using mbed, but want to use Arduino shields? Forget using the newer but smaller capacity M0 Cortex mbeds with Arudino shields. Instead, use the original full M3 Cortex mbed NXP lpc-1768 with 512K Flash, etc. with this adapter.
The mbedR3uino is a vertical shield adapter for the mbed prototyping platform. It provides compatibility with standard Arduino shields including the pins added to Arduino Uno R3 to make shields more independent between main boards. SPI, UART, I2C, Analog, Digital, and PWM pins are wired to appropriate places for Arduino shields, and battery, CAN pins have extra jumpers. This adapter expands upon the (now extinct) mbed workshop board that already provides Ethernet, USB, and SD for the mbed, with the SD SPI pins available as a set of jumpers.
See and read more including schematics at blog: