- #MODBUS POLL INSUFFICIENT BYTES RECEIVED TROUBLESHOOTING HOW TO#
- #MODBUS POLL INSUFFICIENT BYTES RECEIVED TROUBLESHOOTING SERIAL#
- #MODBUS POLL INSUFFICIENT BYTES RECEIVED TROUBLESHOOTING FULL#
- #MODBUS POLL INSUFFICIENT BYTES RECEIVED TROUBLESHOOTING CODE#
However, I’d like also to list down all the other possible ways in order to receive serial UART data with an STM32 microcontroller including the DMA method. This tutorial is intended to be an example application for the DMA unit which we’ve discussed in the previous tutorial (DMA Tutorial). Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network (EPN) and.
#MODBUS POLL INSUFFICIENT BYTES RECEIVED TROUBLESHOOTING FULL#
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#MODBUS POLL INSUFFICIENT BYTES RECEIVED TROUBLESHOOTING CODE#
Has anyone had any success with the Serial Port Class and if possible show an example code for the ReceivedDataEvent that will read data reliably. This heaps of times times with embedded micro's without O/S but making it work with WINCE NET CF is difficult because I cannot control what's happening in the O/S. The documented methods in NET CF seem straight forward enough but in practice I am not getting reliable and consistent operation with the serial port class with un-explained overflow and Timeout exceptions (amongst other things) occuring at times.
#MODBUS POLL INSUFFICIENT BYTES RECEIVED TROUBLESHOOTING HOW TO#
There seems to be very little detailed info and much confusion about serial port operation and I cannot seem to find any official MSFT examples on how this class is used in real world application?īasically all I need to know is how to "RELIABLY" read a packet of serial binary data arriving at the serail port when the DataReceived Event is Fired - seems simple enough but has been causing some pains for weeks! further data processing for applicationįurther to previous post: Can someone please confirm the following details about NET CF 3.5 Serial port operation?Īfter The DataReceivedEvent is fired : Is the receive buffer locked from receiving additional serial data if it arrives?ĭoes reading the data using any of the read methods - remove the read data from the receive buffer - or does one need to use DiscardInBuffer after data has been read? SerialPort.Read(c,0,n) 'reads in serial data Baudrate is 38400 an data lenght can vary between 7 - 60 bytes?Ĭan someone point me in the right direction as how to use the SerialPort.ReceivedDataEvent to properply read in the data of variable unknown length ?ĭim c (128) As Byte 'general array buffer used to store received bytesĭim n As Integer = SerialPort.BytesToRead 'actual data length varies 7 - 60 One problem is that I never know how many bytes will be received as there is no specific termination byte that can be used with MODBUS RTU. Number of bytes received is greater than 7) This works most of the time, but on a number of events SerialPort.BytesToRead returns zero after the event has been fired? ( Have set the Event to fire when the To tell me how many data bytes to read and then read them in using the SerialPort.Read() method. When this event is fired I use the SerialPort.BytesToRead property
The problem I have is when receiving the variable length data using the SerialPort.ReceivedDataEvent. I am using VB code to poll serial data from an external device using MODBUS RTU protocol.