74hct5555 NXP Semiconductors, 74hct5555 Datasheet - Page 6

• Manufacturer Part Number: 74hct5555
• Description: Programmable Delay Timer With Oscillator
• Manufacturer: NXP Semiconductors

Philips Semiconductors
TEST MODE
Set S
S
pulses, this sets all flip-flop stages to a logic HIGH level. Set S
2
HIGH-to-LOW level. This method of testing the delay counter is faster than clocking in 2
FUNCTION TABLE
Notes
1. H = HIGH voltage level
September 1993
24
1
Programmable delay timer with oscillator
and S
. Clock one more pulse into the RS input, this causes a logic 0 to ripple through the counter and output Q/Q goes from
L = LOW voltage level
X = don't care
3
= HIGH-to-LOW transition.
= LOW-to-HIGH transition
to a logic LOW level, this will divide the 24 stage counter into three, parallel clocking, 8-stage counters. Set S
2
MR
to a logic HIGH level, this programs the counter to divide-by 2
H
L
L
INPUTS
A
X
X
B
X
X
6
3
to a logic HIGH level, this causes the counter to divide-by
8
(256). Apply a trigger pulse and clock in 255
one HIGH level
one HIGH level
output pulse
output pulse
Q
L
24
OUTPUTS
(16 777 216) clock pulses.
74HC/HCT5555
Product specification
one LOW level
one LOW level
output pulse
output pulse
Q
H
0
,