Samsung S3F80JB - Manual (Page 265)

COUNTER A S3F80JB
12-4
COUNTER A PULSE WIDTH CALCULATIONS
t LOW
t HIGH
t LOW
To generate the above repeated waveform consisted of low period time, t
LOW
, and high period time, t
HIGH.
When CAOF = 0,
t
LOW
= (CADATAL + 2)
× 1/Fx. 0H < CADATAL < 100H, where Fx = the selected clock.
t
HIGH
= (CADATAH + 2)
× 1/Fx. 0H < CADATAH < 100H, where Fx = the selected clock.
When CAOF = 1,
t
LOW
= (CADATAH + 2)
× 1/Fx. 0H < CADATAH < 100H, where Fx = the selected clock.
t
HIGH
= (CADATAL + 2)
× 1/Fx. 0H < CADATAL < 100H, where Fx = the selected clock.
To make t
LOW
= 24 us and t
HIGH
= 15 us. f
OSC
= 4 MHz, FX = 4 MHz/4 = 1 MHz
[Method 1] When CAOF = 0,
t
LOW
= 24 us = (CADATAL + 2) / FX = (CADATAL + 2) x 1us, CADATAL = 22.
t
HIGH
= 15 us = (CADATAH + 2) / FX = (CADATAH + 2) x 1us, CADATAH = 13.
[Method 2] When CAOF = 1,
t
HIGH
= 15 us = (CADATAL + 2) / FX = (CADATAL + 2) x 1us, CADATAL = 13.
t
LOW
= 24 us = (CADATAH + 2) / FX = (CADATAH + 2) x 1us, CADATAH = 22.