Wavetronix Click 500 (programmable controller) (CLK-500) - Developer Guide - Manual (Page 89)

88 CHAPTER 8 • SERIAL MESSAGE SUPPORT
Note
At the slowest baud rates (e.g. 300 bps) you may need to delay between transmis-
sion of bytes. This can be accomplished using a blocking or non-blocking delay mech-
anism.
Receiving Data
Configuring the message watch list used by the receive message processor to handle the
reception of elected messages on a serial port is accomplished with the ClickMsgAddRe-
ceiveTaskToVPort function. The ClickMsgAddReceiveTaskToVPort function accepts a
ClickMsgString object, a function pointer, and a virtual port identifier. The ClickMsgString
object is the message type you want to listen for, the function pointer is a callback function
you want to be called upon receiving the specified message type, and the virtual port identi-
fier indicates on which port to look for this message. It is recommended to use this function
instead of the older ClickMsgAddReceiveTask function to prevent watch list memory buf-
fers from errantly interleaving partial messages received simultaneously on different virtual
ports.
A Boolean value is returned from the ClickMsgAddReceiveTaskToVPort function indicat-
ing success or failure. A failure will occur when the receive task list is full.
The following code block contains the function Setup1, which shows how to add the Ti-
meRequestMsg string to the watch list. If this message is received on V1, the SetTime call-
back function will be called. The corresponding checksum function DateChecksum is also
added to the checksum array.
void Setup1(void)
{
ClickSerialPortDisconnectAll();
ClickSerialPortConnect(V1, _485TOP);
//ClickSerialPortConnect(V1, _232FRONT);
ClickSerialPortConfigureVirtual(V1, 9600, DATABIT_8,
PARITY_N);
ClickMsgRemoveAllReceiveTask();