Digilent MCC 128 – 16-Bit Voltage Measurement DAQ HAT for Raspberry Pi

• 8 SE/4 DIFF 16-bit voltage inputs
• 100 kS/s max sample rate (320 kS/s aggregate for stacked boards)
• Multiple input ranges (+/-10 V, +/-5 V, +/-2 V, +/-1 V)
• Onboard sample buffers allow high-speed acquisition

The Measurement Computing MCC 128 is a voltage HAT (Hardware Attached on Top) board designed for use with Raspberry Pi®. It provides eight single-ended (SE) or four differential (DIFF) analog inputs with the following input ranges (+/-10 V, +/-5 V, +/-2 V, +/-1 V). A bidirectional clock I/O pin lets users pace operations with an external clock signal or with the board’s internal scan clock. Use software to set the direction. The external digital trigger input is software-configurable for rising or falling edge, or high or low level. The MCC 128 is powered with 3.3 V provided by the Raspberry Pi through the GPIO header connector.

HAT configuration parameters are stored in an onboard EEPROM that allows the Raspberry Pi to automatically set up the GPIO pins when the HAT is connected. The open-source MCC DAQ HAT Library of commands in C/C++ and Python allows users to develop applications on the Raspberry Pi using Linux. The MCC DAQ HAT Library supports operation with multiple MCC DAQ HATs running concurrently. Console-based and user interface (UI) example programs are available for each API.

Screw Terminals

• CH0H/CH0L to CH3H/CH3L (CHx): Analog input terminals.
• Clock (CLK): Bidirectional terminal for scan clock input / output. Set the direction with software. Set for input to clock the scans with an external clock signal, or output to use the internal scan clock.
• Trigger (TRIG): External digital trigger input terminal. The trigger mode is software configurable for edge or level sensitive, rising or falling edge, high or low level.
• AGND (GND): Common ground for the analog input terminals.
• DGND (GND): Common ground for the clock and trigger terminals.

Address Jumpers

• A0 to A2: Used to identify each HAT when multiple boards are connected. The first HAT connected to the Raspberry Pi must be at address 0 (no jumper). Install jumpers on each additional connected board to set the desired address.

Status LED

The LED turns on when the board is connected to a Raspberry Pi with external power applied and flashes when communicating with the board. The LED may be blinked by the user.

Header Connector

The board header is used to connect with the Raspberry Pi.

Scan Clock

The clock input/output (terminal CLK) is used to output the internal scan clock or apply an external scan clock to the device. The clock input signal may be a 3.3V or 5V TTL or CMOS logic signal, and the output will be 3.3V LVCMOS. A scan occurs for each rising edge of the clock, acquiring one sample from each of the selected channels in the scan. For example, when scanning channels 0, 1, and 2 the conversion activity will be:

Trigger

The trigger input (terminal TRIG) is used to hold off the beginning of an analog input scan until the desired condition is met at the trigger input. The trigger input signal may be a 3.3V or 5V TTL or CMOS logic signal. The input condition may be a rising edge, falling edge, high level, or low level.

Firmware Updates

Use the firmware update tool to update the firmware on your MCC 128 board(s). The “0” in the example below is the board address. Repeat the command for each MCC 128 address in your board stack. This example demonstrates how to update the firmware on the MCC 128 that is installed at address 0: mcc128_firmware_update 0 ~/daqhats/tools/MCC_128.fw