no-OS Bare-Metal Software Framework

no-OS is a bare-metal software framework from Analog Devices Inc. designed for systems without an operating system. It is intended for use with lower-end processors (microcontrollers, FPGAs, etc.) that cannot run Linux or a specific OS.

Key features include:

• Platform-agnostic device drivers: Drivers for ADI components that run without an OS.
• Hardware Abstraction Layer (HAL): Allows the same driver to work across various platforms including Xilinx, Intel, Maxim, STM32, ADuCM3029, and Raspberry Pi Pico.
• Ready-to-build project examples: Example projects designed to be flashed to supported evaluation boards.

The display_demo project is a no-OS example designed to demonstrate driving an SSD1306 OLED display using a Xilinx ZedBoard.

Key functionalities include:

• Initializing the SSD1306 display controller via SPI.
• Controlling display power using dedicated VDD and VBAT GPIO controls.
• Printing text messages to the screen.

The initialization data is located in the project source at projects/display_demo/src/app.

The EVAL-ADXL355-PMDZ is an accelerometer evaluation board for high-precision, low-power 3-axis MEMS measurements. It supports selectable measurement ranges of $\pm$2g, $\pm$4g, and $\pm$8g.

Hardware Specifications

• Power Supply: 3.3V from a host board (up to 100 mA).
• Interface: 12-pin PMOD connector for SPI communication.

PMOD Pinout

The AD7124-4SDZ no-OS project provides examples for the AD7124-4, a low-power, low-noise, integrated analog front end. The AD7124-4 features a 24-bit sigma-delta ADC, 4 differential or 7 pseudo-differential input channels, an on-chip 2.5V reference, an internal oscillator, a programmable gain amplifier (PGA), and excitation current sources.

Supported Evaluation Board:

• EVAL-AD7124-4SDZ

Common Applications:

• Temperature and pressure measurement
• Industrial process control
• Instrumentation and smart transmitters

The ADRV903x project provides no-OS drivers and examples for the ADRV9032, a 4-transmitter / 4-receiver (4T4R) integrated RF transceiver. This implementation brings up the ADRV9032 on the ZCU102 carrier using a full JESD204C link managed by the no-OS JESD204 FSM.

Active Profile: UC101 4T4R1OR NLS

• JESD204C: 64B/66B encoding, 8 lanes TX + 8 lanes RX
• Lane rate: 16220.160 Mbps
• DEVCLK: 245.760 MHz (AD9528 channel 1)
• LEMC rate: 7.680 MHz
• Channels: 8 TX / 8 RX IQ channels (4 physical antennas x I + Q)

The ADIS1646X family consists of precision MEMS Inertial Measurement Units (IMUs) containing a triaxial gyroscope and a triaxial accelerometer. This no-OS project provides example implementations for these devices, which include factory calibration for sensitivity, bias, alignment, and linear acceleration.

Supported Evaluation Boards:

• ADIS16465
• ADIS16467
• ADIS16470
• ADIS16475

The FMCDAQ2 no-OS project provides example software for the AD-FMCDAQ2-EBZ evaluation board. This board is an FMC module featuring:

• AD9144: A quad, 16-bit, 2.8 GSPS DAC.
• AD9680: A dual, 14-bit, 1 GSPS ADC.
• AD9523-1: A low jitter clock generator.

Data converters interface with the FPGA carrier board via the JESD204B serial interface. The board is powered through the FMC connector from the attached FPGA carrier board. The UART console for debugging is available at 115200 baud, 8N1 via the carrier board's USB-UART adapter.

The basic variant of the MAX22915 project is a simple example that initializes the device via SPI and demonstrates the following capabilities:

• Switching Control: 8-channel high-side switch control.
• Diagnostics:
  • Open-wire detection (on/off states)
  • Short to VDD detection
  • Overcurrent protection
  • Thermal protection
• Monitoring:
  • ADC-based current sensing per channel
  • On-chip temperature measurement
• Indicators: LED status indicators (FLED for faults, SLED for channel state).
• Data Integrity: CRC protection for SPI communication.

The PULSAR-ADC project provides no-OS examples for the AD4000/AD4001/AD4002/AD4003/AD4020 family of precision SAR analog-to-digital converters (ADCs). These ADCs offer high performance with throughputs up to 2 MSPS (1.8 MSPS for the AD4020).

Supported Evaluation Boards

• EVAL-AD400x-FMCZ

Project Structure

The project uses a variant-based build flow. You select a variant at build time using the --variant <name> flag. The main() function acts as a dispatcher that calls example_main(), which is defined by the selected variant.

• Shared initialization data: Located in src/common.
• Platform-specific macros/init parameters: Located in src/platform.

The basic example demonstrates the integration of the MAX30009 with the no-OS framework. It covers:

• Device initialization and hardware setup
• Interrupt configuration for FIFO data ready
• PLL configuration (e.g., 50 kHz stimulus frequency @ 100 sps sample rate)
• BioZ measurement configuration (sine-wave current drive, 10 V/V gain)
• 4-electrode (tetrapolar) BIA electrode MUX configuration
• Lead-off detection setup
• FIFO data acquisition and sample decoding (I and Q channels)
• Status monitoring (frequency lock, phase lock, power ready)

The LTC3337 is a primary battery state of health (SOH) monitor with a built-in precision coulomb counter. This no-OS project provides an example that initializes the device and continuously reads:

• Accumulated charge
• Battery input/output voltages (with iPeak on and off)
• Die temperature

Results are printed over UART. The project uses common data located in src/common and platform-specific macros located in src/platform.

Hardware Specifications:

• Battery input voltage range: 1.8 V to 5.5 V
• Quiescent current: 100 nA
• Peak input current limits (selectable): 5 mA, 10 mA, 15 mA, 20 mA, 25 mA, 50 mA, 75 mA, 100 mA

The AD74414H is a quad-channel, software-configurable device for industrial control.

Key Features:

• I/O Capabilities: Measures voltage, current, RTD, and thermocouples.
• Converters: 16-bit DAC and 24-bit sigma-delta ADC (with optional 50Hz/60Hz rejection).
• Communication: Integrated HART modem supporting both HART and SPI via configurable pin assignments.
• Diagnostics: Built-in open-circuit/short-circuit detection and adaptive power switching.
• Reference: High-accuracy 2.5V reference.
• Auxiliary Channels: For sensing and power supply measurements.