Electronic Design

DMA Lets 8051 MCU Handle Dual 16-Bit, 1-Msample ADCs

Analog 8-bit microcontrollers are common, but their number approaches zero as the sample rate and resolution grow. Silicon Laboratories' C8051F064 sits at the top of the heap with an 8051-based MCU that has not one but two 16-bit, successive-approximation, analog-to-digital converters (ADCs). An intelligent DMA allows the ADCs to deliver 1-Msample/s throughput with minimal CPU overhead.

The DMA can move ADC information to any peripheral or memory location, including I/O ports, enabling the chip to act as an intelligent ADC. It's even possible to power-down the CPU while this is occurring. The low-noise ADCs use only 20 mW each while maintaining a 0.75-LSB integral nonlinearity (INL). The configuration provides better performance with lower power consumption than an external ADC. The pair of ADCs can be set up for single-ended or differential mode. The 2% on-chip oscillator permits accurate operation without the need for an external crystal or oscillator. Operating voltage is 2.7 to 3.6 V.

The C8051F064's pricing starts at $9.98. It's available in a 12- by 12-mm, 64-pin TQFP package. An eval kit is available for $24.95, and the development kit costs $299.

Silicon Laboratories Inc.

  • Dual, 16-bit, 1-Msample/s ADC
  • Three programmable comparators
  • 2% internal oscillator
  • Digital
  • 25-MIPS 8051
  • up to 64-kbyte flash
  • 4352-byte SRAM
  • external memory interface
  • 5 timers
  • 2 UARTs, SMBus, SPI
  • 24 GPIO
  • Additional digital with 100-pin chip
  • External memory interface
  • 40 GPIO
  • Debug
  • JTAG
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