Linux can also be an I2C slave if the I2C controller in use has slave functionality. For that to work, one needs slave support in the bus driver plus a hardware independent software backend providing the actual functionality. An example for the latter is the slave-eeprom driver, which acts as a dual memory driver. The backend driver and the I2C bus driver communicate via events.
Here is a small graph visualizing the data flow and the means by which data is transported. The dotted line marks only one example. The backend could also use a character device, be in-kernel only, or something completely different:.
Note: Technically, there is also the I2C core between the backend and the driver. However, at this time of writing, the layer is transparent. I2C slave backends behave like standard I2C clients. The only difference is that i2c slave backends have their own address space.
So, you have to add 0x to the address you would originally request. An example for instantiating the slave-eeprom driver from userspace at the 7 bit address 0x64 on bus Each backend should come with separate documentation to describe its specific behaviour and setup. First, the events which are used by the bus driver and the backend will be described in detail. After that, some implementation hints for extending bus drivers and writing backends will be given.
The pointer to val must always be provided even if val is not used for an event, i. Mandatory events must be provided by the bus drivers and must be checked for by backend drivers. Another I2C master wants to write data to us. This event should be sent once our own address and the write bit was detected.
The data did not arrive yet, so there is nothing to process or return. Wakeup or initialization probably needs to be done, though. Another I2C master wants to read data from us. This event should be sent once our own address and the read bit was detected.
After returning, the bus driver should transmit the first byte. Important: This does not mean that the previous byte has been acked, it only means that the previous byte is shifted out to the bus! To ensure seamless transmission, most hardware requests the next byte when the previous one is still shifted out.
If the master sends NACK and stops reading after the byte currently shifted out, this byte requested here is never used. A stop condition was received. This can happen anytime and the backend should reset its state machine for I2C transfers to be able to receive new requests. So, if you extend a bus driver, please make sure that the driver supports that as well. In almost all cases, slave support does not need to disable the master functionality. It is good behaviour to always ACK the address phase, so the master knows if a device is basically present or if it mysteriously disappeared.
Active 5 years, 1 month ago. Viewed times. Marwan Harb Marwan Harb 35 8 8 bronze badges. Uart is a hardware component, it needs time to transfer stuff, but you are not leaving it any. Anyway, working with NIOS both with hardware and software is not that simple, the problem can be anywhere down the chain. Mar 9 '15 at Don't you have to, like, initialize stuff?
Baud rate etc? Do you have to turn the power on the the UART? Does the hardware, cables, connectors etcwork? We can't fix embedded stuff by blog - you have to do it, on site, with the hardware, debugger, scope, terminal emulator etc etc. MartinJames hello, I did sit the the Baud rate when I added the UART component in Qsys, I'm not censored to get right answer at the moment, I just want to see an output, will this code give me an output?
By "leaving no time" I meant, that you are attempting to write the UART over and over again, without waiting the previous operation to be complete.
But as MartinJames says, there are lot of stuff to fix before. Active Oldest Votes. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password.
Post as a guest Name.The use of this design is governed by, and subject to, the terms and conditions of the Intel Hardware Reference Design License Agreement. This reference design is built to work on the Nios II development kits specified below. The I 2 C bus is a simple two-wire, bidirectional interface developed for I 2 C communication with Santa Cruz headers and any I 2 C slave device with compatible pins. This flexible design makes it easy to communicate effectively with the Microtronix I 2 C board.
Three I 2 C bus transmission speeds are supported: Kbps normalKbps fastand 3. Figure 1. These reference design illustrations remain the copyrighted property of Intel or its licensors and may be used within Intel Corporation devices only. They are being provided on an "as-is" basis and as an accommodation, and therefore all warranties, representations, or guarantees of any kind whether express, implied, or statutory including, without limitation, warranties of merchantability, non-infringement, or fitness for a particular purpose, are specifically disclaimed.
I am asking here too because I think it is likely to be quite a different audience. If this duplicate post is against any stack overflow rules or etiquette please let me know and I'll remove it. If not i'll update the forum submission with any answers I receive here and vice versa.
Apparently the version I'm using should just drop into the SOPC and work after being wired to some outputs alterawiki. The core compiles with no errors or warnings. However, when I attempt to write to these registers the write is put into the wrong address whether from my code or manually in debug memory window.
To investigate this I set the registers to initial values in VHDL to see the result in the debug window. This happens whether the write comes from the code or manually from the debug window. This is particularly confusing as writing to these registers works fine in VHDL. I have attempted to debug this from signal tap also. However, triggers on any of the registers are never implemented. However, I decided to throw in the towel for now and use the Verilog version which worked almost straight away when I wired it up.
I intend to get back to the VHDL core when my application is done and will update this again then. Learn more. Asked 6 years, 11 months ago. Active 6 years, 11 months ago. Viewed 2k times. I'd really appreciate if anyone can point me in the right direction here.
Shane Shane 1 1 gold badge 3 3 silver badges 10 10 bronze badges. The code in the question looks as if you are defining one macro and using a different one Also include what defines the address in hardware; i. Apologies, I copied in the wrong define.
I know that my write works because for the first three registers I can write to them fine. To be honest, as this is a 3rd party core, I havnt been able to figure out how the NIOS addresses for each register are defined. In the VHDL each register is just declared as a signal. I can certainly provide a large example of what I'm trying to do overall if that would help? Right now my main problem is why the writes could be re-addressed?
Ah that makes sense. Sorry the "char" cast is part of the define I mistakenly copied in.All of the Verilog and Qsys components are written using Quartus The following diagram shows the overall layout and flow of the software. Figure 44 Software Flowchart. Nearly all extra components on the DE board are used in relation to the camera integration.
The Verilog sets up the initial conditions for the capturing by setting the camera to default values for the capture size and exposure settings and turns it to continuous capture mode. Most of the settings are static but a few can be changed via switches and the push button keys.
These features are listed in the following table. Adjust sensor exposure. Global reset. Stops camera capture. Starts camera capture. Along with adjustments to the camera settings, the Verilog sets up a useful status output. The capture count from the camera is output in hex to the 7-segments displays. This is especially useful to show that the system is current functions and to watch how the key presses affect the processor.
Besides those connections, the rest of the configurations are handled by Qsys and are generated from there. These video pieces are the foundation of a large portion of this program.
It uses just the I2C components to read in data from the camera for video processing. The buttons are also tied into some special functions such as moving the title bar when the button is pressed. These features are shown in the next section since the Qsys is primarily just creating the hardware connections. The user can sit back and watch the camera feed be manipulated automatically by the program. The actual manipulation varies based on the length of time that the program has been running.
The bulk of the code is dedicated to creating the video image. The main components are the clipper, mixer, control synchronizer, scaler and frame buffers. All of these are built-in features of the Altera IP core programs.
The scaler is automatically used when the touchscreen has no user input after a certain amount of time. It can also be trigger by the user when they touch the bottom right corner of the camera feed then either move towards the center of the video or away from it. The mixer lets you combine multiple video streams into one to display on a single screen. This is used to combine a black back layer, the camera feed and the title bar to display on the touchscreen. A layer with a higher number will be displayed over top of the layers of a lower number.
With a layer number of 2, the title bar is always on top of the camera video feed. All of this is loaded into the frame buffer, which is then displayed on the touch screen and monitor.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.
If nothing happens, download GitHub Desktop and try again.
If nothing happens, download Xcode and try again. If nothing happens, download the GitHub extension for Visual Studio and try again. If you're planning to purchase a dev board, consider reading the Hardware section below first. I used version Generate the HDL and the symbol, if you plan to use graphical schematic editor.
Instantiate the generated system in your project and connect its outputs to FPGA pins. If you have less than KB of RAM typically, when using on-chip memorypick "Hello world small" as a base, otherwise pick regular "Hello world". Then add a few settings to project properties:.
Typically, 3. While it's still possible to run some older Arduino libraries using the old toolchain, it was decided it's not worth the effort, so Cyclone II is not supported. If you execute the code from flash, much less RAM is needed, but you will still need more than a real Arduino has, because of the API overhead.
Debugging your software is much easier when the code resides in RAM, so consider getting a dev board with enough on-chip RAM or on-board SDRAM even if you want the execute the code from flash in the end. Try to get at least EPCS16 if you plan to store your code on the board. EPCS16 is also the smallest external serial flash with in-place code execution support.
This project includes a sample SoPC system which should suit most boards. Before it can be used, you should remove components for peripherals not supported by your dev board and those you don't plan to use, and configure the remaining components to suit your hardware and needs as described below:. Only the "tiny" variety is available without restrictions, bigger varieties will be either time-limited or only work while the JTAG cable is connected if you use free edition of Quartus.
SDRAM controller. On many boards, running SDRAM at higher frequencies requires a separate clock with a phase shift compared to system clock: refer to a sample project for your dev board to find out what the correct PLL settings are. On-chip RAM. Its size should be adjusted depending on the usage.
This component can emulate the digital pins of Arduino, so it's required for pretty much anything. You will have as many digital IO pins as you have configured, with a max of Note : After downloading the design example, you must prepare the design template. In releases After entering the project name and folder on the first panel, the second panel will ask you to specify an empty project or project template.
Select project template. You will see a list of Design Templates projects that you have loaded prior as well as various "Baseline Pinout Designs" that contain the pinout and settings for a variety of development kits. If you don't see your design template in the list, click on the link that states install the Design Templates circled below:. Design Store Take a tour. IP Core Note: When a design is stored in the Design Store as a design template, it has been previously regression tested against the stated version of Quartus software.
Prepare the design template in the Quartus Prime software command-line.
This example demonstrates a remote system upgrade using the I2C protocol. The Max 10M50 controls the remote upgrading of the Max 10M08 device. User Guide. Download Quartus Prime v