AN910 Datasheet, PDF (46/51 Pages) STMicroelectronics – ST7 AND ST9 PERFORMANCE BENCHMARKING

ST7 AND ST9 PERFORMANCE BENCHMARKING
9 MEASUREMENT PROCEEDING AND CALCULATION
This section describes measurement proceeding and calculation for computing performance
test routines only. Interrupt processing performance test routines are not concerned
(see <Italic>6.2 Core interrupt processing performance<Italic end> for details on measure
and calculation).
9.1 MEASUREMENT PROCEEDING
The parameters measured are execution time and code size. The first has been measured
on MCU boards (thanks to an oscilloscope) whenever possible, or with the assembly code.
The second has been measured on the assembly code.
To facilitate execution time measurement, assembly code has been divided in two parts. The
first, called Assignments & Initializations in the source code, contains the initialization of the
MCU and data and then a call to the test routine; which is included in the second part, called
Test Loop. The first part ends with an infinite loop. The execution time and code size will
obviously be measured on Test Loop part.
9.1.1 Execution time measure
An I/O pin is used to make the measure, thanks to a digital oscilloscope. This I/O pin is
configured as an output, with a push-pull, and interrupts are disabled in the initialization part.
The pin used for each MCU is detailed in Table 13.
Table 13. I/O pins for execution time measuring
MCU name
80C51XA
68HC16
68HC12
ST9+
ST9
H8/300
68HC11
68HC08
ST7
80C51
KS88
78K0
I/O pin for measure
pin 0 of port 2
pin 2 of port E
pin 7 of port E
pin 0 of port 4
pin 0 of port 4
pin 0 of port 6
pin 0 of port B
pin 0 of port A
pin 0 of port B
pin 0 of port 1
pin 0 of port 2 (for 88C0504)
pin 0 of port 4 (for 88C0116)
pin 0 port 2
The Test Loop routine begins with the set of the I/O pin. This marks the beginning of the test
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