I'm using MPLAB X IDE to implement the transfer of UART data to I2C bus on dsPIC33EV128GM006 using interrupts. How should I start the data transfer if I'm not using the EEPROM or bridge converter IC?
For UART: Port PINS G6 and G7 are being used for communication.
FOR I2C: Port PINS SCL1 and SDA1 are being used for communication.
Baud rate: 9600
Crystal frequency = 32 MHz
The basic goal is to echo the signal from UART to I2C bus to know what data was sent or received on the UART bus.
Working part: UART is working fine with sending characters/strings. I2C is also working fine.
Please let me know the basic logic/approximate flow to implement the goal.
Related
I am trying to flash code over CANBUS on Nucleo-F446. I am referring this application notes
https://www.st.com/resource/en/application_note/cd00264321-can-protocol-used-in-the-stm32-bootloader-stmicroelectronics.pdf
So according to it in Boot mode the default baud rate of CAN is 125KBPS and we need to use PB5 and PB13 pin which are CAN2 pins.
For testing I tried to send CAN message with DLC=0 and STDID = 0x79 for which STM32 should return a ACK with same ID i.e. 0x79.
But I am not getting any response.
You must add a external clock to your Nucleo Board
The system clock is derived from the embedded internal high-speed RC for USARTx and
I2Cx bootloaders. This internal clock is also used for CAN and DFU (USB FS Device) but
only for the selection phase. An external clock multiple of 1 MHz (between 4 and 26 MHz) is
required for CAN and DFU bootloader execution after the selection phase.
STM Bootloader Description
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 am working with ADE7953 metering IC and I use the uart serial communication in raspberry pi to communicate with the IC and i have wiring pi installed in it.Can anyone help me regarding how to configure the IC.
You need to check the datasheets and look for the MODE register configuration. Also take care for the active energy line cycle accumulation mode registers to set before you take IRMS or VRMS any of the ENERGY register
The ADE7953 contains a detection system that automatically
detects which of the three communication interfaces is being
used.
The CS pin (Pin 28) is used to determine whether the
communication method is SPI. The pin must be low
during the SPI communication for this interface method.
The CS pin is active low and will automatically lock onto
SPI communication as a result.
The SCLK pin (Pin 25) is used to determine whether the
communication method is I2
C or UART. If this pin is held
high, the communication interface is set to I
2
C; if it is held
low, the communication interface is set to UART.
Now, for UART should be configured in hardware as pin28 should be high, pin25 should be low, pin 27 Rx and pin 26 Tx
I am working on an embedded project which includes two half duplex UARTS, and one full duplex UART.
UART1 is connected to Device A. UART2 is connected to Device B, and UART3 is connected to the PC. UART1 and UART2 are half-duplex, thus RX/TX modes have to be configured properly.
When a signal on UART1 is triggered, UART2 fetches some data from Device B. That data is put into a buffer, and then transmitted back to UART1, AND UART3. Device A consumes the data, and sends more items on UART1, which then has to be passed to UART2 for Device B to respond.
I was thinking about an efficient state machine that can handle the switching modes between TX/RX mode, and so far my UART code is interrupt driven. What would be some ways to tackle the flow of this program?
I don't think you will need a state machine for this case. Why not just hook up all interrupts accordingly and just forward anything received from one devivce to the other(s)?
You may want to include a TX (ring-)buffer to accomodate for different speeds of each UART and then just have a RX-ISR write the data received to the appropriate TX buffer(s), from where it will then be consumed by the other UARTs' UDRE-ISRs.
I'm trying to interface the Mindwave (http://store.neurosky.com/products/mindwave-1) with my Altys board, through the USB UART port. The dongle I'm trying to connect is basically a wireless reciever that outputs serial data stream on the USB connection. I'm trying to read in this serial stream on the FPGA.
The problem I'm seeing is that when I try to Chipscope the UartRx pin (A16), I see no activity on it even though the dongle is supposed to send 0xAA in standby mode.
Since the FPGA does not power the dongle, I have it connected to an external power USB hub and then connect the hub to the FPGA. However I don't see any activity.
Do I need to convert the signals to another level, or invert them? I thought the EXAR chip takes care of it.
Did you try swapping RX and TX?
Did you have acces to a scope? To check you can repeatly send 'U's (0x55) and look with a scope to see which line is RX and which is TX. You can also check the speed of the interface with this method.