A new crop of 8-bit flash-based microcontrollers (MCUs), designed to use as little power as possible, is on its way. Thus, they're a viable alternative to ROM-based products. Developed by Hitachi Semiconductor America Inc. (www.hitachi.com) and Toshiba America Inc. (www.toshiba.com/taec), they attain their low power by using a variety of power-conserving modes like disabling the flash memory.
Toshiba's TMP86FM48 can run at 8 MHz on 1.8 V or 16 MHz at 2.7 V. The 32 kbytes of flash memory can be reprogrammed using the on-board UART. Nonvolatile storage is provided by 512 bytes of EEPROM. The flash memory can be disabled. Programmable security protection is supported. Peripherals include timers, an analog-to-digital converter (ADC), and an LED driver. Pricing starts at $6.67.
Hitachi's H8/38004 runs at 8 MHz but can downshift 1 MHz while drawing 200 mA. It uses 1.2 mA running at 32 kHz in watch mode. It can switch to full speed in 20 ms. The MCU comes in 32-kbyte flash and 1 kbyte of SRAM. The 16-bit counter can run when the CPU is asleep. Peripherals include an LCD controller, a 10-bit ADC, a UART, and a two-channel PWM timer. Flash pricing starts at $3.75. ROM versions are available.