SN8P2977
8-Bit Micro-Controller with Regulator, PGIA, 24-bit ADC
SONiX TECHNOLOGY CO., LTD
Page 50
Version 1.7
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.
Example: Fcpu instruction cycle of external oscillator.
B0BSET
P1M.0
; Set P1.0 to be output mode for outputting Fcpu toggle signal.
@@:
B0BSET
P1.0
; Output Fcpu toggle signal in low-speed clock mode.
B0BCLR
P1.0
; Measure the Fcpu frequency by oscilloscope.
JMP
@B