The AT91SAM7S321-AU from Microchip Technology is an ARM7 SAM7S microcontroller Integrated Circuit with 16/32-bit architecture, 55 MHz clock, 32 KB (32K x 8) flash in a 64-LQFP (10x10) package.
The AT91SAM7S321-AU-999 from Microchip Technology is an ARM7 SAM7S microcontroller Integrated Circuit with a 16/32-bit architecture, 55 MHz clock and 32KB (32K x 8) flash memory in a 64-LQFP (10x10) package.
The AT91SAM7S321-MU from Atmel is an ARM7 SAM7S 16/32-bit microcontroller Integrated Circuit rated at 55 MHz with 32 KB (32K x 8) flash memory, in a 64-QFN (9x9) package.
The AT91SAM7S321-MU from Microchip Technology is an ARM7 SAM7S 16/32-bit microcontroller Integrated Circuit running at 55 MHz with 32 KB (32K x 8) flash, in a 64-QFN (9x9) package.