U++ forum: Welcome to the forum

Tue, 21 July 2009 17:02

Mindtraveller
Messages: 917
Registered: August 2007
Location: Russia, Moscow rgn.

Experienced Contributor

I`m presenting second part from the latest software. It's RS232 and RS232Protocol classes. Currently they are Windows-only, but it should be simple to add POSIX support for those who has any experience with it.

RS232Protocol class proved itself convenient way organizing any real-life exchange with external devices. It uses U++ style of definitions.

So, let's look how to use it. Let's imagine situation where you have external device with protocol like:
(request) 00AACCDD##
(answer) AA00****##
where
AA = device address (1 byte)
CC = command number (1 BYTE)
DD = some command data
00 = 0x00
** = 1 byte of answer data
## = CRC, simple 8-bit bytes composition

The address of device is addr, command is cmd.

//byte addr;
//byte cmd;
//byte dataR;
//dword ANSWER_TIMEOUT = 500;

RS232 rs232;
RS232Protocol proto1R, proto1A;

proto1R(0x00)(addr)(cmd)(dataR).CRC();
proto1A(addr)(0x00).Word().CRC();

if (!rs232.Open(1)) //COM1
	return;

proto1R.Send(rs232);
if (proto1A.Receive(rs232, ANSWER_TIMEOUT))
{
	word answerData = proto1A[2];
	//...
}

rs232.Close();

Of course it's the simplest example, just to understand the idea.

Attachment: RS232.h
(Size: 9.20KB, Downloaded 479 times)

[Updated on: Tue, 21 July 2009 17:03]

Report message to a moderator