Precision analogue functions in an MCU with Cortex-M3 core

June 30, 2014 // By Graham Prophet
Analog Devices has posted details of an addition to its microcontrollers; for use in areas such as industrial control and automation systems, smart sensors, and precision instrumentation, the ADuCM320 has an on-chip multichannel, 14-bit, 1 Msample/sec A/D converter

The ADuCM320 is a fully integrated single package device that incorporates high performance analogue peripherals together with digital peripherals controlled by an 80 MHz ARM Cortex-M3 processor and integral flash for code and data.

The ADC on the ADuCM320 provides 14-bit, 1 MSPS data acquisition on up to 16 input pins that can be programmed for single-ended or differential operation. The voltage at the IDAC output pins may also be measured by the ADC, which is useful for controlling the power consumption of the current DACs. Additionally, chip temperature and supply voltages can be measured.

The ADC input voltage is 0 V to VREF. A sequencer is provided, which allows a user to select a set of ADC channels to be measured in sequence without software involvement during the sequence. The sequence can optionally repeat automatically at a user selectable rate.

Up to eight voltage D/A converters (VDACs) are provided with output ranges that are programmable to one of two voltage ranges. The VDAC outputs have an enhanced feature of retaining their output voltages during a watchdog or software reset sequence.

Four current D/A converter (IDAC) sources are provided. The output currents are programmable with ranges of 0 mA to 150 mA. A low drift band gap reference and voltage comparator complete the analogue input peripheral set.

The ADuCM320 has a low power ARM Cortex-M3 processor and a 32-bit RISC machine that offers up to 100 MIPS peak performance. Also integrated on chip are 2 × 128 kB Flash/EE memory and 32 kB of SRAM. The flash comprises of two separate 128 kB blocks supporting execution from one flash block and simultaneous writing/erasing of the other flash block.

The ADuCM320 operates from an on-chip oscillator or a 16 MHz external crystal and a PLL at 80 MHz. This clock can optionally be divided down to reduce current consumption. Additional low power modes can be set via software. In normal operating