I have two XBees S1-one attached to a temperature sensor. This Xbee reads analog values, converts them into digital values thanks to the ADC and transmits them.
The other XBee - the receiver, is connected to a computer via a USB Explorer.
This XBee works in API mode. The XBee connected to a computer receives the data send by the transmitter. I monitor the received values with the X-CTU software, version 6.2.0. Up until this point, everything works fine.
However, the problem that I encounter is that the data received on the computer is coded: there are bits corresponding to the address of the receiver, bits corresponding to the address of the sender, the data itself, acknowledgment bits,etc. My question is how can I extract only the data bits without all th other information send by the transmitter?
I tried to read the values with a USB to TTL cable, connecting this cable to the Tx, Rx,GND and 5V(there is a 5V input in the USB Explorer despite that the XBee works at 3.3V) of the receiver XBee and using the screen command in Linux. However, in this way I receive ASCII characters and I want to receive the binary code.
I want to put those values in a database in order to be able to treat them later.
Thank you for your assistance.
With a library like this one, you can use function to get the data from your Xbee in python ;) (if you use linux)
You just have to initialise the port (should be on /dev/tty...) and than catch the data with a loop which check if new data is coming.
If you need more help I can send you part of my code (doesn't have it near me, it's on my raspy)
I hope I've help you ;)
Thana
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I have a third party device that is UART programmable.
I need to create a USB - UART bridge with a functional password (programming only after entering the correct password)
generated the code using the latest version of STM32CubeMX for Atollic TrueSTUDIO for STM32 9.3.0 ...
I transfer data between USB and UART through a buffer (one for usb-uart, and another one for uart-usb)
when I try to transfer several characters everything is OK, but when I try to transfer a large data packet, problems start due to the fact that the USB speed is much higher than the UART ...
there are two questions:
1.How do I tell USB that I need to stop transferring data and wait until the UART (buffer) is busy
2.How on the side of the microcontroller to get the baud rate set on the PC (set when the terminal is connected to the virtual COM port)
USB provides flow control. That's what you need to implement. A general introduction can be found here:
https://medium.com/#manuel.bl/usb-for-microcontrollers-part-4-handling-large-amounts-of-data-f577565c4c7d
Basically, the setup for the USB-to-UART direction should be:
Indicate that the code is ready to receive a USB packet
Receive a USB packet
Indicate that you are no longer ready to receive a USB packet
Transmit the data via UART
Start over
Step 0: Initial setup
Call USBD_CDC_SetRxBuffer to set the buffer for receiving the USB data. Unless you use several buffers to achieve higher throughput, a single call at the start of the program is sufficient.
Step 1: Ready to receive data
Call USBD_CDC_ReceivePacket. Other than what the name implies, this function indicates that the app is ready to receive data. It immediately returns before the data has actually been received.
Step 2: Receive a USB packet
You don't need to do anything here. It will happen automatically. Once it's complete, CDC_Itf_Receive will be called.
Step 3: Indicate that you are no longer ready to receive a USB packet
Nothing to do here. This happens automatically whenever a packet has been received (and double buffering is not enabled).
Step 4: Transmit the data via UART
I guess you know how to do this. It's up to you whether you want to do it in a blocking fashion or using DMA.
Since a callback is involved, you cannot put this code into the main loop. It might be possible to put all code into CDC_Itf_Receive if blocking UART is used. It would appear in the order 2, 3, 4, 1. Additionally, initialization is needed (0 and 1).
In the UART-to-USB direction, you would need to implement flow control on the UART. The USB flow control is managed by the host. Even though USB is much faster than UART, flow control is relevant as the application on the host can process data as slow as it likes to.
Regarding question 2: I'm not sure I understand it... The microcontroller cannot set the baud rate on the host. Either the host can specify a baud rate (transmitted over USB and applied to UART), or if the UART has a fixed baud rate, you can ignore baud rate (any baud rate set on the host side will work as it does not apply to USB).
I use MBED (online IDE & libraries) for my application with host board NUCLEO-411RE and 4D Systems touch display connected by full duplex serial communication.
I am able to send data successfully from host to display without errors. However when sending data from display back to host I am losing data.
Reducing baud to 9600 does not solve the problem.
The host processor remains in a super loop with the first action to check if LCD sends serial data ( lcd4d.readable() ).
Host then receives one character at a time ( lcd4D.getc() ), echos it to the PC via usb ( pc.printf(&recChar) ) and does some further processing.
I am also monitoring the physical host receive pin on a separate terminal session. Using this I am certain that the LCD sends data correctly, however this data is not received and echoed correctly by the host processor (echo to PC is only used for debugging purposes).
Refer to super loop code snippet:
do {
if ( lcd4D.readable() ) {
recChar = lcd4D.getc();
pc.printf(&recChar);
lcd4D_intr_Rx();
}
Also refer to attached screen print showing terminal left PC echo (data loss) and terminal right hardware pin monitor (confirming data sent correctly).
Implementing SerialRX interrupt also does not help the situation with data loss still occurring.
Thanks for any suggestions; I am out of ideas.
I have solved the problem.
The issue was that the host processor needed to respond fast enough to the serial data received. I basically implemented a fast serial receive buffer and ensured that received characters are buffered immediately upon interrupt.
I'm in trouble with programming my Arduino. I've two XBee Series 2 Modules and an Arduino UNO. I use the XBee-API library from: http://code.google.com/p/xbee-api/.
I generate three RemoteATRequest Packets (0x17) to control a Digital Pin of the Remote Sleepy Node and send it out of a SoftwareSerial to the XBee Coordinator which is plugged via a Sparkfun XBee Arduino Shield (https://www.sparkfun.com/products/10854) to the Arduino UNO. The Communication works fine. Every Request Packet is sending out to the Remote. And for every Request Packet a Remote Packet is received. I checked this with a Serial Monitor and a RS232<-> TTL Converter. But in my Arduino Software it seems to be that only one Remote Packet is received. Curious is the point that when I send the Request Packets in the time the Remote is sleeping than I read three Response if it is awake and takes the Requests from the Coordinator.
Does anyone try the same or hase the same problems? I've tried so much until know another Baudrate, delays befor sending out. Nothing works.
My recollection of ZigBee and/or 802.15.4 is that the parent node for a sleepy end device will only hold/queue a single frame for when the sleepy device wakes up. And note that in ZigBee it's only guaranteed to queue it for 7.5 seconds. You may need to modify your code to send a single Remote AT Request at a time, and wait for the response before sending another.
This page has a good description about how the MAC layer works:
Once the frame is assembled, there are actually two ways to send it.
If its going to another router or an end device whose receiver is
always on, the frame will be sent directly via the radio. Otherwise,
if the destination is a sleepy end device, the frame will need to be
sent as an indirect transfer. The frame will go to the indirect queue
until the destination device wakes up and polls the parent. Once the
poll comes in, the frame will get sent to the destination.
It would be great if the XBee module supported a frame type that contains multiple AT commands, but as far as I can tell, that isn't an option.
I'm currently working on a c project, having an XBee Pro Series 1 on my pc, allowing me to send data to my nibo2 roboter, also having that xbee module attached.
Sending data from the nibo2 roboter to my pc works great and there is no kind of data loss.
Sending data from my pc to the nibo2 works not fine:
When I'm trying to send 16 Bytes at one point of time, only the first 8 Byte arrive at my nibo2. The second 8 Byte are lost. When i send the data split into 8 Bytes and send them with a time difference of maybe 1s - 2s, it works fine.
The maybe interesting things you should know about this, are listed here:
XBee Datasheet: http://ftp1.digi.com/support/documentation/90000982_H.pdf
The used library for the roboter (using uart0): http://nibo.sourceforge.net/doc/html/
Does anyone have an idea or does someone know the problem? Is it a thing about configuring the xbee module? interrupt problem?
Thanks a lot.
How have you configured the XBee modules? Which firmware version? What baudrate? Are you using hardware flow control (CTS and RTS signals)?
Can you use the "Assemble Packet" button on Terminal tab of X-CTU on the PC to send the 16-byte packet and have it received properly?
Can the serial port of the NIBO2 handle 16 bytes in one request? Does it work if you use a wired connection instead of wireless?
I have a SPI for MSP430 written. If I send WRSR(01h) or RDSR(05h) to M25P64 flash.
The response I get from the Flash SPI_MISO is FFh.
So my question is "Is the response I have obtained is it right?"
How do I come to an understanding that handshaking between my SPI and Flash is correct?
Thanks
AK
Is the response I have obtained is it right?
The response is wrong. 30 seconds on Google and in the datasheet will tell you that. Things to check (since you have not provided any information):
How do I come to an understanding that handshaking between my SPI and Flash is correct?
Is this a new piece of SPI code? If so have you checked with an oscilloscope to see what you send out (clock and MOSI) is what you expect and matches what the datasheet says the device expects? It's the definitive way to be sure.
Does your SPI code work with any other devices?
Are your IO pins configured correctly on the MSP430?
Have you got the SPI module configured correctly for phase and polarity?
Did you forget to assert the chip select line?
What about HOLD?
Did you remember to send a dummy byte after the RDSR command so that the device would send the status register value?
Do you see a response from the device on an oscilloscope? Does the MSP430 read that value or a different one?
You are sometimes better first of all trying to read the device ID rather than the status register for a new piece of code. The reason for that is the device ID will never change, whereas the status register might change (although that depends on the device).