Mutex information

17.5.6 Mutex information

The mutex information defines ID number: mtxid, Attribute: mtxatr, Reserved for future use: ceilpri for a mutex.

The number of items that can be defined as mutex information is limited to one for each ID number.

The following shows the mutex information format.


CRE_MTX (mtxid, { mtxatr, ceilpri });

The items constituting the mutex information are as follows.

1 ) ID number: mtxid

Specifies the ID number for a mutex.
A value from 0x1 to 0xff, or a name, can be specified for mtxid.

Note When a name is specified, the CF850V4 automatically assigns an ID number.
The CF850V4 outputs the relationship between a name and an ID number to the system information header file in the following format:

 #define mtxid   value

2 ) Attribute: mtxatr

Specifies the task queuing method for a mutex.
The keyword that can be specified for mtxatr is TA_TFIFO or TA_TPRI.

TA_TFIFO: Task wait queue is in FIFO order.

TA_TPRI: Task wait queue is in task priority order.

3 ) Reserved for future use: ceilpri

System-reserved area.
Only values from "0x1 to maximum task priority maxtpri defined in Basic information" can be specified for ceilpri.