8051 core at 18 MHz — ROMless by design
The Maxim Integrated DS80C323-END+ is an 8-bit microcontroller built around the 8051 core, clocked at 18 MHz. It is a ROMless device — there is no on-chip program memory — so code must reside in external Flash, EPROM, or SRAM accessed through the EBI/EMI interface. The 256 x 8 bytes of internal RAM serve as scratchpad and register file. This architecture suits designs where the firmware image is large, field-updated via external memory, or already committed to a separate boot ROM.
The 32 general-purpose I/O pins, plus the UART/USART and SIO serial interfaces, give enough connectivity for a sensor hub or a human-machine interface panel.
Housed in a 44-pin TQFP (10x10 mm body) with surface-mount leads. The supplier device package is 44-TQFP (10x10).
Peripherals and watchdog
On-chip peripherals include a power-fail reset and a watchdog timer (WDT). The power-fail reset generates a clean reset when the supply drops below the trip threshold, which is useful for battery-backed or unreliable-mains designs. The WDT can be used to recover from firmware lockups without an external supervisor IC.