3.3
Real-time Sampling Analysis
Notes on acquisition of graph data through Real-time sampling analysis are listed below.
- | It may not be possible to identify the sampling interval, depending on the number of graphing targets registered. |
- | It may not be possible to acquire graph data.
If acquiring data has failed, lines between transition points are not displayed but only the time information is displayed (see “(a)Graph“). |
- | When graph data of a 2-, 4-, or 8-byte variable is to be acquired, the process of assigning a value to the variable may be divided into two steps (see "ExampleWhen using the RL78 microcontroller").
If sampling of the variable takes place between the two steps, an incorrect value may be read out because the assignment is not completed. |
Example | When using the RL78 microcontroller |
In this example, if sampling takes place before "(2)" is executed, the value of variable "value_a" in which only the assignment to the two lower-order bytes has been completed is read out.
[C source text]
long int value_a = 0; // Definition of a 4-byte variable
void func(void)
{
value_a = 4000000000; // Assignment to a 4-byte variable
}
|
[Assembly instructions for the assignment processing above]
MOVW AX, #2800H
MOVW !_value_a, AX ;(1): Assignment to the two lower-order bytes of variable "value_a"
MOVW AX, #0EE6BH
MOVW !_value_a+2, AX ;(2): Assignment to the two upper-order bytes of variable "value_a"
|