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| − | {{TOC right}}
| + | #REDIRECT [[Kart]] |
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| − | [[File:Kart_sensors_module.jpg|center|1000px|Sensors module]]
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| − | Various sensors can be mounted on the [[Kart/Motherboard|motherboard]] through the exposed [https://digilent.com/reference/pmod/start PMOD] connectors.
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| − | == Hall sensors ==
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| − | One or two Hall sensors are used to track the distance driven by the kart.
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| − | The [http://sensing.honeywell.com/honeywell-sensing-ss311pt-ss411p-product-sheet-005914-1-en.pdf SS311PT/SS411P]
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| − | digital Hall-effect sensors are operated by a magnetic field and designed to respond to alternating North and South poles with their
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| − | [https://en.wikipedia.org/wiki/Schmitt_trigger Schmitt-trigger] output.
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| − | They can be powered between 2.7 Vdc to 7 Vdc, with an open collector output (which integrates a 10 kOhm pull-up resistor already).
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| − | Thus it can be operated through any PMOD by wiring it such as:
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| − | :{| cellpadding="3" cellspacing="0" border="1"
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| − | ! Color
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| − | ! Pin
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| − | |-
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| − | | Red
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| − | | 3.3 V power supply
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| − | |-
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| − | | Brown
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| − | | Hall output
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| − | |-
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| − | | Black
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| − | | GND
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| − | |}
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| − | {{WarningBox|content=
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| − | No internal pull resistor should be enabled on the FPGA side.
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| − | }}
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| − | ==== Operating procedure ====
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| − | To enable and root the hall sensors, proceed as follow:
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| − | * Modify the '''Kart/Kart_Student''' package variable '''NUMBER_OF_HALL_SENSORS''' to the number of used hall sensors
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| − | * Modify the .pdc file to root the halls to the desired pins
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| − | ** <code>set_io {halls[1]} -pinname 86 -fixed yes -DIRECTION Input</code>
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| − | ** ''{halls[n]} with n from 1 to NUMBER_OF_HALL_SENSORS''
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| − | ==== FPGA design ====
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| − | [[File:Kart_hall_block.jpg|right|700px|hall sensors block]]
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| − | To begin with, the [[Kart#FPGA_Design|design environment]] has to be downloaded.
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| − | It comprises the <code>sensorsController</code> block which contains the registers and events manager
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| − | and an empty <code>hallCounters</code> block which is to be completed.
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| − | The <code>hallPulsesFilter</code> block does the following:
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| − | * It receives the raw pulses from the hall sensors
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| − | * It debounces the input to avoid false-transitions
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| − | * It finally transmits the filtered pulses
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| − | The <code>hallCounters</code> block then receives the <code>hallPulses</code> signal array (i.e. one signal per hall pulse sensor, from 1 to NUMBER_OF_HALL_SENSORS).
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| − | The following behavior must be implemented:
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| − | * While '''zeroPos''' (also from 1 to NUMBER_OF_HALL_SENSORS) is '1' for a sensor, reset the pulses count
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| − | * Then, if '0', the dedicated counter must be incremented on either:
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| − | ** The '''rising edge''' of the pulse
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| − | ** Both the '''rising and falling edges''' of the pulse
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| − | {{WarningBox|content=
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| − | Please modify the '''Kart/Kart_Student''' package variable '''HALLSENS_2PULSES_PER_TURN''' to '1' if the signal is counted
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| − | on each edge or '0' if counted only on the rising edge.
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| − | }}
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| − | * The counters values must be concatenated to the '''hallCount''' signal (e.g. for 2 sensors : hallCount = (COUNTER2 << 16) + COUNTER1)
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| − | {{WarningBox|content=
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| − | The output '''hallCount''' must '''ALWAYS''' reflect the current counters values
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| − | }}
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| − | * When '''zeroPos''' goes to '1', the corresponding counter value must be immediately reset on the next clock
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| − | *''The signal '''hallChanged''' is unused.''
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| − | {{TaskBox|content=
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| − | Draw the schematics of the <code>hallCounters</code> block.
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| − | }}
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| − | == Ultrasound ranger ==
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| − | An ultrasound ranger can detect if there is an obstacle at the front or back of the kart.
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| − | It is based on the [https://digilent.com/reference/pmod/pmodmaxsonar/start PMOD-MAXSONAR] board from Digilent,
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| − | and can be plugged into any one-row PMOD connector ('''beware not to wire on the +12V pin !''').
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| − | The ranger will output a pulse named '''PW''' on the board whose length has to be counted to determine the distance to an object following the rule 147 us / inch.
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| − | Since the start/stop pin is not reachable, the sensor will continuously output pulses between 0.88 and 37.5 ms, each 49 ms.
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| − | {{WarningBox|content=
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| − | No internal pull resistor should be enabled on the FPGA side.
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| − | }}
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| − | ==== Operating procedure ====
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| − | To root the ranger, proceed as follow:
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| − | * Modify the .pdc file to root the ranger to the desired pin
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| − | ** <code>set_io distancePulse -pinname 63 -fixed yes -DIRECTION Input</code>
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| − | ** The pin must correspond to the '''PW''' pin on the ranger board
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| − | ==== FPGA design ====
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| − | To begin with, the [[Kart#FPGA_Design|design environment]] has to be downloaded.
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| − | It comprises the <code>sensorsController</code> block which contains the registers and events manager
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| − | and an empty <code>ultrasoundRanger</code> block which is to be completed.
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| − | The <code>rangerSubsignals</code> block is responsible to transmit the pulse internally only 3 times per second and to synchronize the signals to the beginning of the pulse.
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| − | It creates two signals:
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| − | *<code>countEnable</code>, which stays at '1' the length of the measurement
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| − | *<code>countPulse</code>, which are small pulses that must be counted, dividing the clock by a factor 10 (else the total count may be bigger than its corresponding [[kart/serial link#Registers|register]])
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| − | The block <code>ultrasoundRanger</code> has the following flow:
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| − | * wait for the signal <code>countEnable</code> to be '1'
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| − | * when so, the pulses <code>countPulse</code> must be counted as long as <code>countEnable</code> is '1'
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| − | * when it goes back to '0', the counter value must be output to the <code>distance</code> signal and the counter reset, waiting for <code>countEnable</code> to go back to '1'
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| − | {{TaskBox|content=
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| − | Draw the schematics of the <code>ultrasoundRanger</code> block.
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| − | }}
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| − | == End of turn switch ==
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| − | The end of turn switch can be plugged into any PMOD connector, respecting the following:
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| − | :{| cellpadding="3" cellspacing="0" border="1"
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| − | ! Color
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| − | ! Pin
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| − | |-
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| − | | Green
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| − | | PMOD I/O
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| − | |-
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| − | | Black
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| − | | GND
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| − | |}
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| − | {{WarningBox|content=
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| − | An internal pull-up must be enabled on the FPGA side.
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| − | }}
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| − | ==== Operating procedure ====
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| − | To root the switch, proceed as follow:
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| − | * Modify the .pdc file to root the switch to the desired pin
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| − | ** <code>set_io stepperEnd -pinname 97 -fixed yes -DIRECTION Input -RES_PULL Up</code>
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| − | == LEDs / Low-consumption outputs ==
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| − | In addition to the [[Kart/Daughterboard#LEDs|3 indication LEDs present on the daughterboard]], one can use any PMOD to drive [https://digilent.com/shop/pmod-8ld-eight-high-brightness-leds/ LEDs]
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| − | or other outputs requiring either ON, OFF, or 50% duty cycle PWM (from 1 to 16383 ms) output.
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| − | {{WarningBox|content=
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| − | The consumption per pin cannot be higher than 8 mA.
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| − | If needed, use a [https://digilent.com/shop/pmod-od1-open-drain-output/ driver extension board] to control voltages other than 3.3V or higher currents (through MOSFETs).
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| − | }}
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| − | Check with your supervisor before wiring custom systems.
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| − | I/O lines are '''NOT''' protected against over current and voltage backfeed.
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| − | You are held responsible for the cost of repair in the event of destruction of the equipment (up to 50CHF per board).
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| − | ==== Operating procedure ====
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| − | On the FPGA side, those outputs are called leds[n].
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| − | To root them, proceed as follow:
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| − | * Modify the '''Kart/Kart_Student''' package variable '''NUMBER_OF_LEDS''' to correspond to how many outputs are used
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| − | * Modify the .pdc file to root the leds to the desired pins
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| − | ** <code>set_io {leds[1]} -pinname 78 -fixed yes -DIRECTION Output</code>
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| − | ** ''{leds[n]} with n from 1 to NUMBER_OF_LEDS''
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| − | == Buttons / Digital inputs ==
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| − | [https://digilent.com/shop/pmod-btn-4-user-pushbuttons/ Buttons] or other digital inputs can be wired to any PMOD '''as long as their levels are in the range 0-3.3V !'''
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| − | An event is sent to the smartphone each time the input is rising or falling.
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| − | {{WarningBox|content=
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| − | Inputs are not suitable for signals faster than 5 Hz.
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| − | By the design and use of a BLE system, the transmission channel would become congested.
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| − | }}
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| − | ==== Operating procedure ====
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| − | On the FPGA side, those inputs are called endSwitches[n].
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| − | To root them, proceed as follow:
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| − | * Modify the '''Kart/Kart_Student''' package variable '''NUMBER_OF_EXT_END_SWITCHES''' to correspond to how many inputs are used
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| − | * Modify the .pdc file to root the inputs to the desired pins
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| − | ** <code>set_io {endSwitches[1]} -pinname 64 -fixed yes -DIRECTION Input</code>
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| − | ** ''{endSwitches[n]} with n from 1 to NUMBER_OF_EXT_END_SWITCHES''
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| − | ** If needed, one can add <code>-RES_PULL Up</code> or <code>-RES_PULL Down</code> to use internal pull resistors
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| − | == Proximity sensors ==
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| − | The [[kart/sensors/VCNL4000|proximity sensors]] are used to get the ambient light along the ''close'' proximity to an object.
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| − | They can be plugged in any PMOD.
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| − | '''''They are normally not used anymore and thus not tested in the current Kart project.'''''
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| − | The sensor cable is to be connected as:
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| − | :{| cellpadding="3" cellspacing="0" border="1"
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| − | ! Color
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| − | ! Pin
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| − | |-
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| − | | Orange
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| − | | 3.3 V power supply
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| − | |-
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| − | | Yellow
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| − | | SDA
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| − | |-
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| − | | Green
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| − | | SCL
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| − | |-
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| − | | Blue
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| − | | ground
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| − | |}
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| − | {{WarningBox|content=
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| − | External pull-ups should be present on the sensor board I2C lines, else internal ones enabled on the FPGA side.
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| − | }}
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| − | ==== Operating procedure ====
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| − | To root them, proceed as follow:
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| − | * Modify the '''Kart/Kart_Student''' package variable '''NUMBER_OF_PROXIMITY_SENSORS''' to correspond to how many sensors are used
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| − | * Modify the .pdc file to root the SCL to the desired pin(s)
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| − | ** <code>set_io SCL_proxy -pinname 27 -fixed yes -DIRECTION Input -RES_PULL Up</code>
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| − | ** ''if using multiple sensors and the SCL pins cannot be wired to the same output, root the <code>SCL_proxy</code> to multiple pins''
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| − | * Modify the .pdc file to root the SDAs to the desired pins
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| − | ** <code>set_io {SDA_proxy[1]} -pinname 28 -fixed yes -DIRECTION InOut -RES_PULL Up</code>
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| − | ** ''{SDA_proxy[n]} with n from 1 to NUMBER_OF_PROXIMITY_SENSORS''
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| | [[Category:Kart]] | | [[Category:Kart]] |
