Hookup Guide for the SparkFun RedBoard Artemis
Nate, Ell C 
Hardware Overview
If you've ever used an Arduino Uno before you should be pretty familiar with the various female headers and the barrel jack power. If you're new to Arduino boards, check out the SparkFun RedBoard Qwiic tutorial for more information on many of the basic board functions you'll see on the Artemis RedBoard. In this tutorial we'll be covering the unique aspects of the RedBoard Artemis.
The ADC on the Artemis is 0-2V. Exposing an ADC pin to 3.3V will not harm the device but the ADC will saturate returning 16,383 (14-bit) for voltages greater than 2V.
GPIO
Looking at the front of the Artemis RedBoard, you'll notice that alongside the female headers are plated through-holes. We've found that while we enjoy the ease of using the headers, sometimes we just want to solder directly to our board. To that end, we've added the PTH rails. Note that these are NOT all ground pins - these pins have whatever functionality is labeled beside their female header companions.
Serial and JTAG Programming
The RedBoard Artemis has two methods for programming. The most common is the USB C connector that operates as a USB to serial bridge. By simply pressing 'Upload' in the Arduino IDE or 'make bootload' from the SDK the firmware on Artemis is updated.
We use the CH340C on the RedBoard Artemis. The driver should automatically install on most operating systems. However, there is a wide range of operating systems out there. You may need to install drivers the first time you connect the chip to your computer's USB port or when there are operating system updates. For more information, check out our How to Install CH340 Drivers Tutorial.
How to Install CH340 Drivers
August 6, 2019
The second method is JTAG programming. An unpopulated JTAG footprint is available for more advanced users who need breakpoint level debugging. We recommend checking out our JTAG section for the compatible male header and a compatible JTAG programmer and debugger.
Mic and RTC
The Artemis exceeds at low power voice recognition. To enable this we've included a PDM MEMS microphone on the board. Additionally, the Artemis module can operate an RTC given an external 32kHz crystal so we've included that was well.
Qwiic and I2C
The I2C pins on the Artemis are labeled SDA and SCL. They are controlled in the Arduino IDE using Wire.begin(), Wire.read(), etc. The same SDA/SCL pins are connected to the Qwiic connector so you can use SparkFun's Qwiic ecosystem (there's over 50 boards and more every week!).
Serial0, AREF, and USB Pads
On the rear of the RedBoard are some advanced features. Normally, an AREF pin is located between the SDA and GND pins. The Artemis module has no equivalent pin so we've converted that pin to GND. If you have a shield that utilizes the AREF pin or just want to free it, you can cut the AREF jumper and the labeled 'GND' located between SDA and GND will be left disconnected.
On Artemis, TX0/RX0 are used for bootloading new code and Serial.println() statements to the computer's terminal window. The CH340C takes care of the serial to USB conversion. However, if you need access to these pins, they're available. TX0/RX0 can be used as GPIO as well as special functions, but for most applications these pins are left as Serial for bootloading.
For users who are embedding the RedBoard Artemis into an enclosure the USB pads are exposed so that an external USB connector can be located at the edge of the enclosure and wired back to the USB pads.
Busmaster Pads
One amazing aspect of the Artemis is the large number of SPI and I2C buses available. We at SparkFun decided that it would be better to have more PWM and ADC pins routed to the female headers on the front of the board, rather than extra I2C and SPI pins. But we just couldn't resist! We've made Wire1/SPI1 and Wire3/SPI3 available to users through the SMD pads on the bottom of the board. These pins can be used as GPIO if needed and pins 28/29 are PWM enabled as well.
Current Measurement Jumper
The Artemis can run as low as 6μA/MHz meaning the module can run at 48MHz at less than half a milliamp. To enable measurements and to isolate the power hungry devices (such as the LM317 voltage regulator) we've added a NC (normally closed) jumper. By cutting the jumper the VDD trace to the module is interrupted. Soldering in a male jumper or wires into the accompanying holes will give you the ability to insert a current meter and precisely monitor how much current your application is consuming.
For the vast majority of projects a wall adapter or USB power can be used. But when properly isolated the Artemis can run on a coincell battery for weeks! So we've designed in a 20mm SMD coin cell footprint so that users can experiment with powering the Artemis from a standard CR2032. You can pickup the compatible coincell holder here.
Bypass Jumper
USB C is wonderful. It's reversible and can source up to 2 amps at 5 volts without any power delivery (PD) negotiation. We've included a 2A resettable fuse (often called a PTC) on the Artemis as a safety feature in case your project decides to consume inordinate amounts of power (And possibly begins to spark and set fire. That was fun wasn't it? Get it? SparkFun?). In the event the RedBoard begins to pull more than 2 amps from the USB source, the resettable fuse will automatically trigger and disconnect the board from the computer or power supply. This should protect your power source and the traces on your RedBoard.
However, there are plenty of legitimate projects that need more than 2A. We've designed the power traces to withstand up to 2A with a 10C rise in temperature. If your power supply can provide adequate power, and you know what you are doing, you can close the BYP jumper circumventing the resettable fuse.
