Project: hep026
Author: Joseph D Warner <warner.512@osu.edu>
Organization: The Ohio State University
Version: 0.1
Date: 2014/07/11
This software aims to control the BPM Data Acquisition System that is being built for CERN for use on Proton Sychrotron particle accelerator to collect data from beam profile monitors (BPM) located at IRRAD-1.
This software is designed to work with the hep026 rev. 1 board designed by Joseph Warner of The Ohio State University ATLAS Group. If this software is not being used with that board but instead with some equivalent board, certain constants may need to be updated in defines.h. The microcontroller daughter board used in this project is the Arduino Yun which has basic information detailed below.
The Arduino Yun is an open source prototyping board that is designed with two processors: ATmega32u4 and the Atheros AR9331.
The ATmega32u4 controls all of the input and output pins on the Arduino Yun. It provides a pinout digaram on Arduino's official website showing the mapping between the pins on the mcu and their function on the Arduino Yun. A summary of its functionality is provided below taken from the official product page of the Arduino Yun.
| Microcontroller | ATmega32u4 |
|---|---|
| Operating Voltage | 5V |
| Input Voltage | 5V |
| Digital I/O Pins | 20 |
| PWM Channels | 7 |
| Analog Input Channels | 12 |
| DC Current per I/O Pin | 40 mA |
| DC Current for 3.3V Pin | 50 mA |
| Flash Memory | 32 KB (of which 4 KB used by bootloader) |
| SRAM | 2.5 KB |
| EEPROM | 1 KB |
| Clock Speed | 16 MHz |
The Atheros AR9331 provides a linux based operating system for the Arduino Yun. It is connected to an ethernet port and WiFi radio that allow communication via the Internet. A short summary of its capabilities is provided below from the official product page of the Arduino Yun.
| Processor | Atheros AR9331 |
|---|---|
| Architecture | MIPS @400MHz |
| Operating Voltage | 3.3V |
| Ethernet | IEEE 802.3 10/100Mbit/s |
| WiFi | IEEE 802.11b/g/n |
| USB Type-A | 2.0 Host |
| Card Reader | Micro-SD only |
| RAM | 64 MB DDR2 |
| Flash Memory | 16 MB |
The hardware constants defined in defines.h are mapped to physical pins on the hep026 board and on the Arduino Yun itself.
The serial interface of the Arduin Yun are a fixed set of pins, Digital 0 (RX) and Digital 1 (TX). These pins on the ATmega32u4 are connected directly to corresponding serial pins on the Atheros AR9331. Thus, it is not reccommended to modify what pins are used for serial communication as it will prevent any communication between the two processors on the Arduino Yun.
/* Serial Interface */
#define PIN_SERIAL_RX PD2 // D0
#define PIN_SERIAL_TX PD3 // D1
The 16 bit analog-to-digital converter on the Arduino Yun is operates with four pins: Digital 2 (SDA), Digital 3 (SCL), Digital 4 (ALERT_RDY), and Digital 5 (ADDR). These pins are all directly mapped to the corresponding pins on the ads1115 chip on the hep026 board. It is not reccomended to move SDA and SCL from pins 2 and 3 because these pins on the Arduino Yun have hardware interrupt capabilities provided by the ATmega32u4.
/* I2C Interface */
#define PIN_I2C_SDA PD1 // D2
#define PIN_I2C_SCL PD0 // D3
/* ADC Control */
#define PIN_ADC_ALERT_RDY PD4 // D4
#define PIN_ADC_ADDR PC6 // D5
On the hep026 board, there are 8 multiplexers that determine which integrator is currently sending data towards the ADC. These multiplexers are 3-to-8 converters. They are separated into two sets: MUX1 and MUX2. MUX1 is a single multiplexer that controls which multiplexer in MUX2 will output to the integrators. MUX2 is a set of 7 integrators which determine which integrator channel will output.
The precise placemenet of this pins on any board seeking to have a similar control mechanism is not necessary, however care should be taken to change all outputs rapidly on the microcontroller when changing which integrator channel is active.
/* MUX 1 Selection */
#define PIN_MUX1_SEL1_A PD7 // D6
#define PIN_MUX1_SEL1_B PE6 // D7
#define PIN_MUX1_SEL1_C PB4 // D8
/* MUX 2 Selection */
#define PIN_MUX2_SEL2_A PB5 // D9
#define PIN_MUX2_SEL2_B PB6 // D10
#define PIN_MUX2_SEL2_C PB7 // D11
The functionality of these pins is to the HOLD and RES gates on the acf2101 integrators on the hep026 board.
The HOLD pin is used to disconnect the input current and hold the output voltage at a fixed level. When reading data from the integrator into the ADC, HOLD should held high (1). When collecting data from inputs, HOLD should be held low (0).
The RES pin is used to discharge the capacitors in the acf2101 integrators. When discharging the capacitors, RESET should be held low (0), otherwise it should be held high (1) at all times. The state of HOLD does not matter when discharging the capacitors.
If making a similar board, care should be taken to ensure that thee is sufficient output current from these pins to drive the acf2101 integrators.
#define PIN_INT_RES PD6 // D12
#define PIN_INT_HOLD PC7 // D13
The hep026 board has two external triggers that provide it information about when data collection should occur. There are the Trigger and CPS signals. When they change state, it is expected that board begin or stop collecting data.
These pins do not need to be connected to interrupts as polling is fast enough to detect the signals.
/* External Inputs */
#define PIN_EXT_TRIGGER PF7 //A0
#define PIN_EXT_CPS PF6 // A1
To use this software you will need to compile it and then load it onto the microcontroller.
To compile this software you must run
make
To then subsequentely load the compiled program onto the microcontroller run
make program
To clean the build directory of the project run
make clean
All files listed under the lib directory are provided by other individuals. The names of each library and their licenses are listed below.
Author: Elia <elia@eliaselectronics.com> http://eliaselectronics.com