Single-chip pulse programmer for magnetic resonance imaging using a 32-bit microcontroller

Abstract

An MRI pulse programmer has been developed using a single-chip microcontroller (ADμC7026). The microcontroller includes all the components required for the MRI pulse programmer: a 32-bit RISC CPU core, 62 Kbytes of flash memory, 8 Kbytes of SRAM, two 32-bit timers, four 12-bit DA converters, and 40 bits of general purpose I/O. An evaluation board for the microcontroller was connected to a host PC, an MRI transceiver, and a gradient driver using interface circuitry. Target (embedded) and host PC programs were developed to enable MRI pulse sequence generation by the microcontroller. The pulse programmer achieved a (nominal) time resolution of approximately 100 ns and a minimum time delay between successive events of approximately 9 μs. Imaging experiments using the pulse programmer demonstrated the effectiveness of our approach