ls7055 LSI Computer Systems, Inc., ls7055 Datasheet - Page 4

• Manufacturer Part Number: ls7055
• Description: 6 Decade Predetermining Up/down Counter
• Manufacturer: LSI Computer Systems, Inc.

MANUAL
R E S E T
7055-012703-4
MAINSIGNAL, PRESIGNAL,
ZERO DETECT OUTPUT
PRESET ENABLE
LSD +4 OUTPUT
DIVIDE CONTROL
STORAGE SELECT
INPUTS
COUNT INPUT
DATA TRANSFER
INPUT
MSD OUTPUT
INHIBIT
INTERNAL PRESET
7 SEGMENTS
OUTPUTS
BCD OUTPUTS
COUNT INHIBIT
INHIBIT
INTERNAL RESET
BCD DATA
INPUT
UP/DOWN
SCAN CLOCK
INPUT
RESET
AUTOMATIC
R E S E T
FIGURE 2. AUTOMATIC OR MANUAL OPERATION IN UP MODE
*
T
UDH
COUNTER AT
MAINSIGNAL VALUE
COUNTER AT
PRESIGNAL VALUE
COUNTER AT
Z E R O
T
ppw
T
ds
*
BCD data input assumed to be applied from a set of thumbwheel switches as shown in Figure 5.
ZERO DETECT OUTPUT
MAINSIGNAL OUTPUT
PRESIGNAL OUTPUT
T
T
gb
rpw
T
T
do
dth
FIGURE 4. TIMING DIAGRAM
MANUAL
P R E S E T
T
T
dh
udh
T
AUTOMATIC
P R E S E T
FIGURE 3. AUTOMATIC OR MANUAL OPERATION IN DOWN MODE
cs
T
do
T
gb
COUNTER AT
PRESET NUMBER
COUNTER AT
PRESIGNAL VALUE
COUNTER AT
MAINSIGNAL
NUMBER
COUNTER AT
Z E R O
T
iph
T
irh
T
PRESIGNAL OUTPUT
MAINSIGNAL OUTPUT
ZERO DETECT OUTPUT
ch