SN8P2711A
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 54
Version 0.1
4.5.1 SYSTEM CLOCK MEASUREMENT
Under design period, the users can measure system clock speed by software instruction cycle (Fcpu). This way is
useful in RC mode.
¾
Example: Fcpu instruction cycle of external oscillator.
B0BSET
P0M.0
; Set P0.0 to be output mode for outputting Fcpu toggle signal.
@@:
B0BSET
P0.0
; Output Fcpu toggle signal in low-speed clock mode.
B0BCLR
P0.0
; Measure the Fcpu frequency by oscilloscope.
JMP
@B
Note: Do not measure the RC frequency directly from XIN; the probe impendence will affect the RC
frequency.