I want to drive a birectionnal logic signal through the FPGA.
PGD_ICD <--> PGD_TARGET
for those who have recognized the Microchip ICD3 you know that PGD line is bidirectional.
I've read that we can't do something like that but have you any idea ?
many thanks
Passing a bidirectional bus through an FPGA without knowing the bus protocol won't work.
While FPGA I/O pins do support tristate logic signals (floating output state), you will need to know when to drive a value onto the output, and when to tristate the output (high impedence, or 'Z').
Once you have a signal (for example out_enable) that is '1' when you want to drive a value and '0' when the output should be floating, you can use a tri-state buffer to drive the output:
out_pin <= out_signal when(out_enable='1') else 'Z';
Related
I know that you can turn on a vehicle signal (for example, the left indicator) in traci using:
traci.vehicle.setSignals(vehID, int)
where the integer related to the specific signal can be found using the following link (https://sumo.dlr.de/docs/TraCI/Vehicle_Signalling.html#signaling), but is there a way of turning off a specific signal that would be otherwise turned on by the program (i.e., a setSignalOff)?
I think that there is a function in the underlying C++ code (switchOffSignal() in MSVehicle.h) but there doesn't appear to be a traci command that turns off a specific signal.
I appreciate that it is (generally) a pleasant visual aesthetic and has no impact on vehicle behaviour, but it would be very useful for what I am trying to do!
Switching off signals should work from traci. By using sometihng like traci.vehicle.setSignals("ego", 0), I can switch them off. Be aware that this will be reset after the step, so you may have to do that in every timestep.
So, Michael is right in that:
traci.vehicle.setSignals("ego", 0)
should turn off all signals (although the signals still appeared on for me visually, which confused me initially).
To turn off individual signals but keep the others on you need to:
For all the "on" signals find the value of 2^n, where n is the bit integer (which can be found using the following link: https://sumo.dlr.de/docs/TraCI/Vehicle_Signalling.html)
Sum all these 2^n values (let's call this variable x) and use this value in the setSignals function: traci.vehicle.setSignals("ego", x).
So for example, if we want the brake light, the right indicator and the high beam on (but all the other signals off) we would do:
RightIndicatorValue = pow(2,0)
BrakeLightValue = pow(2,3)
HighBeamValue = (2,6)
SignalValue = RightIndicatorValue + BrakeLightValue + HighBeamValue
traci.vehicle.setSignals(("ego", SignalValue)
Context: I am following an embedded systems course https://www.edx.org/course/embedded-systems-shape-the-world-microcontroller-i
In the lecture on bit specific addressing they present the following example on a "peanut butter and jelly port".
Given you a port PB which has a base address of 0x40005000 and you wanted to access both port 4 and port 6 from PB which would be PB6 and PB4 respectively. One could add the offset of port 4(0x40) and port 6(0x100) to the base address(0x40005000) and define that as their new address 0x40005140.
Here is where I am confused. If I wanted to define the address for PB6 it would be base(0x40005000) + offset(0x100) = 0x40005100 and the address for PB4 would be base(0x40005000) + offset(0x40) = 0x40005040. So how is it that to access both of them I could use base(0x40005000) + offset(0x40) + offset(0x100) = 0x40005140? Is this is not an entirely different location in memory for them individually?
Also why is bit 0 represented as 0x004. In binary that would be 0000 0100. I suppose it would represent bit 0 if you disregard the first two binary bits but why are we disregarding them?
Lecture notes on bit specific addressing:
Your interpretation of how memory-mapped registers are addressed is quite reasonable for any normal peripheral on an ARM based microcontroller.
However, if you read the GPIODATA register definition on page 662 of the TM4C123GH6PM datasheet then you will see that this "register" behaves very differently.
They map a huge block of the address space (1024 bytes) to a single 32-bit register. This means that bits[9:2] of the the address bus are not needed, and are in fact overloaded with data. They contain the mask of the bits to be updated. This is what the "offset" calculation you have copied is trying to describe.
Personally I think this hardware interface could be a very clever way to let you set only some of the outputs within a bank using a single atomic write, but it makes this a very bad choice of device to use for teaching, because this isn't the way things normally work.
I am working on a project where I'm trying to implement I2C master-slave communication so as to read some data from a magnetic sensor. That's all OK and I have written the code. However, I am not quite sure about the slave address needed for the communication to actually happen. The board I'm using can hold STM32 ARM® Cortex™-M3 and Cortex™-M4 MCU's. I don't know if it matters, but the MCU I'm using is STM32F107VCT6.
The part of the code where I need to enter the address is in the following function marked as "SLAVE_ADDRESS_GOES_HERE":
uint8_t Magnet_readReg(const uint8_t regAdd)
{
uint8_t pom[1] = {0};
pom[0] = regAdd;
I2C1_Start();
I2C1_Write(SLAVE_ADDRESS_GOES_HERE, pom, 1, END_MODE_RESTART);
I2C1_Read(SLAVE_ADDRESS_GOES_HERE, pom, 1, END_MODE_STOP);
return pom[0];
}
The results should be some numbers which tell me how strong the magnetic field is. It has three different values as an output because it calculates a value for each of the three axes (yes, it's the correct plural of the word axis), so it can could be used as a compass for example.
Now the trick is that I don't get any results because I don't know the actual address of the sensor. Therefore, I will share the datasheet of the sensor I'm using. I am not sure if i'm reading it correctly.
Here is the datasheet:
https://www.memsic.com/userfiles/files/Datasheets/Magnetic-Sensors-Datasheets/MMC3416xPJ_Rev_C_2013_10_30.pdf
Solved.
As it turns out, there was something wrong with the board itself. Therefore, a connection couldn't be established. And the address is 60H for writing and 61H for reading. 30H is the address, but when you add a zero or a one in the LSB position you get 60H or 61H.
The I2C address of your sensor is described on page 4 of the datasheet you provided. You must read the marking on your device package, then use the table from "Number" to "Part number" in the datasheet to determine your exact part. Finally, use the table under the "Ordering Guide" to find the factory-programmed I2C slave address of your device.
Given that you later specified that your 7-bit I2C slave address is 0x30, then you must have part number MMC34160PJ, which should be marked:
0 •
XX
I Have a simple function in FPGA ( like an adder ) but I want to this adder get the inputs from PC from ( Quartus II )
for example I want to add two 12 bit number but I haven't enough switches .
How get input from pc and send them to FPGA and How get them in FPGA ?
(I just have USB Blaster Cable )
Since you are already using the USB Blaster, you could use the in-system sources and probes feature. That will allow communication to and from the FPGA through the USB Blaster.
ISSP
I am trying to get to get familiar with working with a 74LS148 Priority Encoder IC. I am providing a 5 Volt constant current voltage source to the IC and have a 0 Volt ground Voltage. I tried connecting every input to the 5 Volt source to set it on a HIGH logic state, which should give, according to the truth table, HIGH in the output. Then tried setting some inputs to LOW, but that had no effect in the output which remained in a HIGH state.
I then tried using pull up resistors, the use and circuit configuration of which is not entirely clear to me, which I think is the problem. I connected the resistors as shown in the picture below, which should give a HIGH state in the output. I then tried connecting some inputs, along with their resistors, to the Ground. The output still remained on a HIGH state, around 4.3 Volts.
I repeated the entire process with another 74LS148 IC to make sure the first one was working.
I'd could really use a little help. Thank you all!
74LS148 has the following truth table:
EI (pin-5) must low (connect to ground)
The enable E1 must be ground. you also your diagram indicates inputs 0 through 7 are pulled high. This will always produce your outputs to be HIGH
I think you should include a bleeder resistor at output to draw some constant current. This will help regulator function as desired.