Tag Archives: ADC


STM32 Analogue-to-Digital Converter (ADC)

STM32 Clock Tree

Most of us who have experienced 8-bit MCUs previously know how much important it is to have an Analogue-to-Digital Converter (ADC) built-in with a microcontroller. Apart from other hardware extensions unavailable in the early era microcontrollers, many former 8051 microcontroller users shifted primarily to more robust Atmel AVRs and Microchip PICs just for this important peripheral. I don’t feel it necessary to restate the advantages of having such a peripheral embedded in a micro. In traditional 8-bit MCUs aforementioned, the ADC block is somewhat incomplete and users have to work out tricky methods to solve certain problems. The ADC block of STM32 micros is one of the most advanced and sophisticated element to deal with in the entire STM32 arena. There are way too many options for this block in a STM32 micro. In this issue, we will explore this block. ADC Hardware Block Diagram Read more

XMega ADC

ADC Characteristics

For users of advance MCUs like the XMega it is not necessary to tell what an analog-to-digital converter (ADC) is or what it does. I assume this is not the first family of microcontroller they are dealing with. Unlike the ADCs of other microcontroller the ADC of XMega devices is a highly complex tool. The level of complexity is so much that without understanding every bits-and-pieces of this piece of hardware a user won’t enjoy its absolute power. XMega ADC is also the most confusing hardware as it is not like other MCU ADCs. We will be dealing with ATXMega32A4U and it has only one ADC block, named ADCA but some other XMega devices like the XMega128A1 have more than one ADC block – ADCA and ADCB. By the way the XMega reference manual provides a long literature on the ADC and I’m not willing to state everything.

A quick view of the ADC block diagram shows most of the internal arrangement.

ADC internal

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Microchip announces new 16-bit A/D converters with 200Msps sampling rate

adc

Microchip Technology Inc. has announced two families of new high-speed A/D converters in the MCP37DX1-200 and MCP372X1-200 families. These families feature 12-, 14- and 16-bit pipelined A/D converters with a maximum sampling rate of 200 Mega samples per second (Msps). The 14- and 16-bit devices feature high accuracy of over 74 dB Signal-to-Noise Ratio (SNR) and over 90 dB Spurious Free Dynamic Range (SFDR), while the 12-bit devices have 71.3 dB SNR and 90 dB SFDR. This enables high-precision measurements of fast input signals. These families operate at very low-power consumption of 490 mW at 200 Msps including LVDS digital I/O. Lower power-saving modes are available at 80 mW for standby and 33 mW for shutdown.

The MCP37DX1-200 and MCP372X1-200 include various digital processing features that simplify system design, cost and power usage for designers. These families also include decimation filters for improved SNR, individual phase, offset and gain adjustment and a fractional delay recovery for time-delay corrections in multi-channel modes. Data is available through the serial DDR LVDS or parallel CMOS interface and configured via SPI. An integrated digital down-converter is included in the MCP37DX1-200 family making it ideal for communications applications. The 12-bit families include an integrated noise-shaping requantizer, which enables users to lower the noise within a given band of interest for improved accuracy and performance. These families are targeted for applications in the communications markets such as base stations, test equipment, and IF receivers, among others.

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DIY directional control input pad

Directional input pad

This DIY directional pad will allow you to provide user inputs or to navigate through the LCD menu in your microcotroller based project. It has got five input tact switches that are readable through one ADC channel. The resistor divider network on board provides a unique analog voltage for each key press which can be identified through an ADC channel.

Directional input pad

 

chipKIT Tutorial 3: Analog-to-digital conversion

ADC output displayed on serial monitor

We live in an analog world where most physical variables are analog signals. However, a microcontroller can only process data that is available in digital format. It is precisely for this reason that the analog-to-digital conversion (ADC) is so important in embedded systems that interact with an analog environment. In this tutorial, we will discuss about the ADC capabilities of chipKIT UNO32 board and illustrate how to read an analog input signal from its ADC channels.

Analog-to-digital conversion

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