neoPLC 8-Channel Analog Input

An excellent way to extend the accuracy and number of inputs on your microcontroller, this 12-bit precision analog-to-digital converter provides 8 channels of accurate voltage measurement. The voltage automatically adjusts to the logic level voltage, making this board compatible with 3V to 5V microcontrollers. Capable of 50000 samples per second, speed will never be a concern. For extreme precision, the ADC can be configured as 4 differential channels instead. Includes solder jumpers to chain as many as 4 boards together for a total of 24 channels. As with all neoPLC boards, this unit operates at logic levels from 3 to 5 volts, is controlled with our neoPLC library, communicates using only 2 wires over i2c, and is 100% tested before shipping.

Technical Notes

this is a sinking supply, meaning that it connects the pins to ground when they are closed (on), and leaves them floating at the supplied power voltage when open (off). This allows very efficient N-channel FET design, and leads to the high current capability. All channels are, by default, synchronized. Our library includes an optional ‘efficient’ mode which distributes the duty over the channels being used in a manner that minimizes changes in current draw to help protect batteries and other power sources. We do not recommend this product for switching voltages above 12V (see the DMN1019 datasheet).

neoPLC – “professional prototypes, no compromises”

• Easy wiring – all our boards use i2c serial, so no matter how many boards are in use, they share the same four wires – so you can be connected and running in no time
• Easy chaining – the boards share the same serial wires– allowing trouble-free connection of multiple boards – even boards with different functions!
• No ‘extra’ pins are broken out – you never have to dig through datasheets to connect these boards
• The boards can be stacked for easy testing, or soldered edge-to-edge creating a professional rapid-prototype for demonstration and small production products
• All code is contained in a single (open-source) library, but only the code you need is compiled to your micro-controller, saving space and increasing speed
• All boards operate from 3 to 5.5 V – safe with most common microcontrollers
• Uniform pricing – all boards of all functions are $20 – easily estimate total project costs
• Every board is tested for performance before shipping

Wiring

First, provide the neoPLC boards a common ground (GND) and a power bus V+ (anything from 3-5V for all our boards!). Secondly, i2c uses two lines to communicate – a ‘Serial CLock’ (SCL) bus and a ‘Serial Data’ (SDA) bus. Simply connect these to the appropriate pins on your microcontroller and neoPLC board, and you’re all set. Can’t be much easier than 4 wires! One more, very important thing – you must connect a ‘pullup’ resistor (between 1kOhm and 5kOhm) between the SCL and SDA bus. GND, V+, SCL, and SDA are clearly labeled on all neoPLC boards. The SCL and SDA pins on common microcontrollers are listed in the table below:

How does i2c work?

One of the key benefits of the neoPLC boards is the simple wiring. Nearly all modern microcontrollers include a dedicated i2c (pronounced ‘eye-squared-see’) port. Standing for ‘inter-integrated-circuit’, i2c is clever as allows many integrated circuits to share the same communication and power lines – the ‘bus’. The SCL clock is controlled by your microcontroller, it provides a steady march of pulses while communicating to ensure no data is missed by either component. While the SCL steadily pulses, the microcontroller and neoPLC board take turns sending and receiving data over the SDA bus. Each board has a name in i2c called its ‘slave address’. When the microcontroller sends a specific board’s name out on the SDA bus, that board alone will respond. So, many boards can share the same SCL and SDA bus, but only if they have unique addresses – otherwise everyone gets confused about who should be speaking! To allow multiple identical boards on the same bus, we provide adjustable address ‘pads’ on most boards: by cutting the same trace near A0,A1,etc. and putting a small dab of solder on the other side of the pad, the address is changed. Multiple combinations of cut/uncut traces allows several boards to be connected.

Downloads

Datasheet is available in the Right Sidebar Uses the ADS7828 library by deskwizard