McuSerial Class Reference

MCU serial communication handler. More...

List of all members.

Public Types
enum	Status { unknown, error, cmd_ok, ans_ok }
Signals
void	status (bool bOpen, McuSerial::Status eStatus)
Public Member Functions
bool	open (const QString &qsPort)
void	close ()
bool	send (IMcuCmd *pCmd)
bool	recv (IMcuAns *pAns, int nTimeout=200)
void	flush ()
Static Public Member Functions
static void	msleep (int nMsecs)
Static Private Member Functions
static QString	hex (const QByteArray &aData)
Private Attributes
QextSerialPort *	m_pSerPort
bool	m_bOpen
Status	m_eStatus
QString	m_qsLastCmd

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Detailed Description

MCU serial communication handler.

This class encapsulates the serial port that is used to talk to the MCU.

It provides methods for passing commands described by IMcuCmd derived classes to the MCU and filling in the received answers.

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Member Function Documentation

bool McuSerial::send

(

IMcuCmd *

pCmd

)

Send command pCmd over serial line to MCU

Typically send() is followed by an immediate recv(). Except a few special cases, a flush() should be issued before send().

Note:

: Care must be taken with conversions from/to QChar and QString:

• Strings that are sent/received from the MCU must be converted with toLatin1()/fromLatin1()
• Strings that come from source code must be converted with the editor's encoding, here fromUtf8()
• Strings that are output to the debugging console must be converted with LQS() (i.e. toLocal8Bit())

See also:

recv(), flush()

bool McuSerial::recv	(	IMcuAns *	pAns,
		int	nTimeout = 200
	)

Recieve answer pAns from MCU serial line

Typically recv() is called immediately after send().

Since the communication with QExtSerialPort seems to be very fragile when attempting to read more answer characters than available, an iterative approach is chosen:

• query pAns for the expected answer length with IMcuAns::receive()
• read all currently available answer characters up to rnMax from the serial line; if less than rnMin bytes are available, wait 50 msecs and retry receiving one time.
• hand over received data to pAns, again with IMcuAns::receive(). If further answer data is expected (returned number != 0), loop. If looping 4 times with rnMin > 0 and no answer data available, abort with a timeout log message. This is important to not block the GUI if e.g. connection to the MCU broke down.

Note:

: Care must be taken with conversions from/to QChar and QString:

• Strings that are sent/received from the MCU must be converted with toLatin1()/fromLatin1()
• Strings that come from source code must be converted with the editor's encoding, here fromUtf8()
• Strings that are output to the debugging console must be converted with LQS() (i.e. toLocal8Bit())

See also:

send()

void McuSerial::flush

(

)

Flush serial receive queue.

For most commands, it is recommended to flush the receive queue befor sending a new command, to avoid stale answer bytes spoiling the real answer to this command.

There are exceptions where flushing is not wanted, i.e. while receiving a PEC table, where commands for reading each PEC value are issued and then all answers are read (for performance improvement).

See also:

send(), recv()

void McuSerial::msleep

(

int

nMsecs

)

[static]

Sleep nMsecs milliseconds

Note:

: Use with care: will stall the GUI while sleeping when called from GUI thread

QString McuSerial::hex

(

const QByteArray &

aData

)

[static, private]

Return binary data oData as hexdump and string of characters, with non-printable characters replaced by "."

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The documentation for this class was generated from the following files:

• /media/_value/value/devel/astro/aspect/aspect/src/mcuserial.h
• /media/_value/value/devel/astro/aspect/aspect/src/mcuserial.cpp

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