Mitsubishi Electric Q12DCCPU-V User Manual page 265

9
PROGRAMMING USING BUS INTERFACE
FUNCTIONS
The following flowchart shows the outline in the case of a user watchdog timer error
interrupt.
(2) Precautions for using the bus interface functions
(a) Programming precautions
Interrupt routine (interrupt program) start
Access the SRAM data. *2
(QBF_WriteSRAM/QBF_ReadSRAM function)
*2
Register the event history.
(QBF_RegistEventLog function)
Interrupt routine (interrupt program) end
Figure 9.4 User watchdog timer error interrupt programming outline
1) Open/close processing
Perform the bus open and close processing (QBF_Open function/QBF_Close
functions) only once at the beginning and end of the program respectively.
Communication performance will decrease if open/close is repeated at each
communication.
2) Simultaneous processing of bus interface functions
Bus interface functions are serialized in the C Controller module for
processing.
When the MELSEC data link function are requested simultaneously in multiple
tasks, one of the task starts its processing and the other tasks will have to wait
until the processing is complete.
3) User watchdog timer error interrupt
When using the bus interface functions on multiple tasks, register the routine
for the user watchdog timer error interrupt from one of the tasks.
4) Clock setting
When setting the clock of the C Controller module, confirm that both the
QBF_WaitEvent and QBF_WaitUnitEvent functions are not in process.
5) Remote STOP/PAUSE and bus interface function execution result
When the operation status of the C Controller module is remote STOP or
remote PAUSE, the execution result of the following operations by the user
program will be STOP/PAUSE error.
• Output (Y) (QBF_Y_OutBitExfunction, QBF_Y_OutWordEx function)
• Buffer memory writing (QBF_ToBuf function)
Y output and buffer memory writing can be executed from the <<Module
monitoring>> tab of the C Controller setting utility.
6) The sequence program control function (QBF_ControlProgram function) can
be executed only to the High Performance model QCPU.
7) For tasks that use bus interface funtions, do not use a mutual-exclusion
semaphore that specifies the SEM_INVERSION_SAFE option.
9.5 Programming Flow for Bus Interface Functions
*2 Specify "1" (ISR) for the argument of the
function, "sFlg" since starting from inerrupt
routine (interrupt program).
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