I am using MPU6050 onboard a GY-86 module. I also have a DS3231 RTC module. when i searched each data sheet i found that DS3231 and MPU6050 have same i2c address which is 0x68. I have read in the MPU data sheet that if i connect the AD0 pin to 3.3 the the address becomes 0x69. but i can't find any AD0 on my module . i only have vcc-3.3v-SCL-SDA-INTa-FSYNC-DROY
I think i have to change i2c address of mpu6050 or ds3231. so that they won't conflict . how can i change i2c dress of MPU or DS module.
Looking at the GY-86 schematic I found, the AD0 pin is hard grounded on the board. This means that unless you can find a trace on the board to cut (unlikely), there is no way to change the MPU6050 slave address. As far as I can see, the DS2321 cannot change its address either.
This leaves you with a few choices:
Change out on of the devices to a different model with a different address. I expect you really don't want to do this.
If your master device (which you did not specify) has multiple I2C bus controllers, hook each device to a different bus.
Use an I2C multiplexer to put the devices on different "virtual" busses. Here's a module with a 1-8 multiplexer which should do the job (though only a 1-2 is really necessary).
Related
I'm trying to establish Modbus RTU connection (for learning purposes) between two PC's (Win10). I'm using two USB to RS485 converters (D- connected together and D+ also connected together). This converters are connected to USB2.0 ports.
USB to RS485 converter
So I'm using "Modbus Poll" and "Modbus Slave" from "modbus tools".
First computer act as slave and has the following settings:
Slave configuration
Slave definition
Second computer act as master and has following settings:
Master configuration
Master definition
And my problem is, everytime i get "Timeout error":
Timeout error
So, what I'm doing wrong? I'm pretty sure converters are not damaged, because Win10 detecs them.
After all I just want to send simple value to another computer (via Modbus RTU) :)
Thanks
Well, this is not a real answer but I can provide some debugging suggestions.
In the past, I had problems with that RS-485 hardware you're using. It didn't work and I'm not sure why. The one I have uses a strange logic to drive DE pin of the MAX485. If I remember correctly, it inverts the TX line coming from CH340G using a NAND gate and feeds it to DE pin. I'm not sure if it was the problem, but I don't think it's a good design.
You may need pull-up and pull-down resistors on RS-485 lines to prevent it from floating when no driver is driving the bus. Some converters include them internally. Also, you may need 120 ohm termination resistors on both ends.
Instead of working with RS-485, you can simply use TTL logic for testing purposes. Use two USB-TTL converters, connect TX to RX (cross connection).
When debugging communication buses (USART, SPI, I2C etc.) always use logic analyzers. Even the cheapest one saves hours of debugging time.
you need to install proper drivers. I used following link which includes a how to video as well as download link for the drivers . Also disable RTS as its 2 wire RS485 so RTS cant be used.
I know there was an armv5 and armmv6 data sheet for this kind of thing, but there is none for the armv8, at least no publicly given. I went through: https://people-mozilla.org/~sstangl/arm/AArch64-Reference-Manual.pdf
I didn't actually read through all of it, but parsing things like: System timer, clock, peripherals, base address... is not giving me any satisfactory results.
All I want is a list of base addresses telling me what the base peripheral address is, and what the system clock's relative address is, and what the mailbox relative address is... and any and all other memory mapped peripherals.
The ARM Architecture Reference Manual is not where the peripherals or the memory map are described. ARM is not a chip, it is a licensed processor core IP built into chips by various licencee manufacturers who implement their own peripheral designs around it.
Broadcom provide the SoC for RPi, and it is a proprietary chip used internally by Broadcom, so that publish limited public data. The published Broadcom peripheral documentation refers to the RPi1's BCM2835 but is mostly identical to the RPi2 BCM2836 and RPi3 BCM2387 with respect to the peripheral set.
The documentation also contains a section for the RPI 3 specifically: Link which says:
This is the Broadcom chip used in the Raspberry Pi 3, and in later models of the Raspberry Pi 2. The underlying architecture of the BCM2837 is identical to the BCM2836.
So you can look up the docs for the Pi 2 on a sibling page Link which say:
The underlying architecture in BCM2836 is identical to BCM2835.
which is at: Link
So I guess you can somewhat trust in the PDFs for the Pi 1 and Pi 2 pages:
Link with errata at: https://elinux.org/BCM2835_datasheet_errata
Link
My dad wants me to make kind of a smart home.
I would like to interface with KNX (a home automation protocol) using the GPIO on a Raspberry Pi 3. Ideally, I would like to build a web interface for it, but I don't have a clue how to interface with KNX in the first place.
Any suggestions?
It wont make sense for you to interpret and understand the KNX bus communication protocol directly. There is a massive specification behind the KNX bus which deals with so many problems from device addresses to collision detection. It would take years to master it and unless you develop KNX devices you really should not spend your time on it. You will be better off by doing the following:
Buy a KNX/IP gateway/interface such as https://www.mdt.de/en/products/product-detail/system-devices/system-devices/ip-interface.html
Understand that KNX bus traffic can be routed/tunneled to your home LAN/WIFI
Play around with one of the KNX libraries on GitHub. For example for C#: https://github.com/search?l=C%23&q=knx&type=Repositories&utf8=%E2%9C%93
If you want, have a look at my experimental .NET Core project which starts a radio streaming process when someone touches a button (in the bathroom in my case). It runs on any operation system (so Raspberry and Linux are fine) and you can find it here: https://github.com/ThomasZeman/KnxNetCore
check this website : http://michlstechblog.info/blog/raspberry-pi-eibknx-ip-gateway-and-router-with-knxd/ that might help. also there are special knx 2 ip devices sold by electronic stores
You can't connect the KNX bus to anything on the pi. The KNX bus has its own electrical specs, and you need specialized hardware to connect to it.
Such hardware is available, but probably a KNXnet/IP device (such as the Siemens N148) is a better option.
I see two options for you:
A) use an IP interface (e.g. the ones from MDT) and access the IP interface from your raspberryPi (e.g. with http://calimero-project.github.io/)
B) use a TPUART controller, which makes KNX TP telegrams accessible (r/w) to UART - see http://www.konnekting.de/konnekting-lernen/l1-knx-mit-arduino/
I'm interested in interfacing an STM32-based flight controller with external sensors based on the SPI (Serial Peripheral Interface) protocol. I have a couple of FCs (Flip32 F3, shown in attached photo; EMAX Skyline 32) that have a section of pins marked 5V/GND/RST/SCK/MISO/MOSI, which I presume are there to support ISP (In-System Programming); i.e., these pins allow the FC to act as a slave device for a programmer device that acts as the master. Other boards, such as the multiFlite NANO-B-FC, provide pin headders explicitly for SPI (other attached image), with CS (Chip Select) instead of RST.
Am I correct in these assumptions: i.e., the first kind of pinout (RST/SCK/MISO/MOSI) does not support an external SPI sensor, and the latter (CS/SCK/MISO/MOSI) does?
Flip32 F3 flight controller; ISP pads upper-left:
MultiFlight Nano-B flight controller pin header schematic:
I don't know these boards, just had a look at some pics on the internet.
The Flip32 F3 seems to have an Atmel ATMEGA microcontroller on board. (as an auxiliary MCU) I would assume that the 6 pins you found are the ISP interace for that MCU.
Just use a multimeter in continuity test mode and check if the 6 pads are connected to the ISP pins of the ATMEGA.
The board's main MCU STM32 is more likely programmed through the SWD (serial wire debug) interface. That's a pin-reduced JTAG alternative. Just google for it.
Here are some details if you are interested in Atmels ISP:
http://www.atmel.com/images/doc0943.pdf
If the firmware supports it (or you write one that supports it) you should be able to use the ISP interface as a normal SPI interface which it basically is.
ISP is usually done through a simple serial interface like JTAG, SWD or in the AVR case SPI.
Best way to find out: Read the datasheet of your ATMEGA.
I am using ‘SH72867(Renesas)’ connect with ‘EEPROM(24LC04B)’ . In the customer’s document at ‘address 0xF0 of EEPROM have data 0x5555’, But when I reading from this address always return ‘0xFFFF’ and same with other address.
I can’t write to EEPROM too.
I used I2C sample of Renesas but not run.
Do you have any suggestion about setting up I2C?
Sorry for my bad English and no clear explanation.
Any help apprciated,
Thanks
Verify the common issues:
Data and clock are connected properly.
Pull up resistor on clock and data connected to VCC.
Loop the I2C read request, connect scope and verify that I2C signals are OK. In addition check the ACK bit.
Verify clock is lower then 400kHz.
When using code examples, they usually fit to specific board. Verify that the code example configuration is the same as your board.
Some MCU may have more then one I2C pinout options. The code example might use I2C module that connected to diffrent pins.