HTF_BITS
TIMEOUT
READOUT
BUSY

32-bit integer

This register communicates status information about the current state of the system. Two bits (1, 2) are used to determine if the PCI board has data available for reading or if the board is ready to except more commands. The DSP has an input/output FIFO that can hold a maximum of six 16-bit words at any given time. To prevent commands and parameters from being lost, due to a full FIFO, bit 1 is checked before sending a command or data, and bit 2 is checked before reading a reply data value, such as the current pixel count. If bit 1 is set, the input FIFO is empty and a command or data can be sent. If bit 2 is set, the output FIFO is not empty and a reply data value can be read. The bit summary is given below:

    Check before sending a command or command parameter:
        Bit 1 = 1 Host input FIFO is empty, can send command
                0 Host input FIFO is not empty, cannot send command

    Check before reading a reply data value:
        Bit 2 = 1 DSP output FIFO is not empty, can read data
                0 DSP output FIFO is empty, no data

Three bits (3, 4, 5) are used to communicate replies from both the PCI board and the controller. The default value is 0, which would mean a timeout has occurred if the bits are not changed to one of the other values before a specified amount of time has elapsed. A value of 1 means the last command completed successfully. A value of 2 means the last command has generated a reply data value, which is now avaiable for reading from the Reply Buffer. A value of 3 means an error has occurred and the last command has failed. A value of 4 means a system reset has occurred and may or may not be an error, depending on the command. A value of 5 means the controller is currently reading out an image and cannot be interrupted or process ascii commands. A value of 6 means the PCI board is currently busy processing a command and cannot be interrupted. The device driver will wait for one of the other reply values to be set before returning.

    Bits 3, 4, 5
        = 0 TIMEOUT (Timeout)
        = 1 DON (Done)
        = 2 RDR (Read Reply Value)
        = 3 ERR (Error)
        = 4 SYR (System Reset)
        = 5 READOUT (Readout)
        = 6 BUSY (PCI Busy)

CController class methods that use these values:
IsReadout
GetPCIStatus

NAME	DESCRIPTION	VALUE
HTF_BITS	A bit-mask for the HTF ( Host Transfer Flags ) that is used in conjunction with the CController::GetHstr() method. The resulting value will be one of the remaining values.	0x00000038
TIMEOUT	The last command failed to receive a reply from the PCI board or controller.	0
READOUT	The controller is currently reading out image data.	5
BUSY	The PCI board is busy. The user must wait until this is cleared before it will accept any new commands.	6

        // Demonstrates how to check if the controller
        // is in readout before sending more commands.

        #include <iostream.h>
        #include "CController.h"
        using namespace std;
        using namespace arc;

        CController cController;

        try {
            // .... open driver, initialize, etc ....

            lHstr = cController.GetHstr();

            if ( ( ( lHstr & HTF_BITS ) >> 3 ) == READOUT )
                throw std::runtime_error( "Cannot send command; controller reading out!" );

            // .... do some command ....
        }
        catch ( std::exception &e )
        {
            cerr << "Exception Occurred: " << e.what() << endl;
        }