COUNTER AT
PRESET NUMBER
MAINSIGNAL OUTPUT
COUNTER AT
MAINSIGNAL VALUE
PRESIGNAL OUTPUT
AUTOMATIC
RESET
COUNTER AT
PRESIGNAL VALUE
PRESIGNAL OUTPUT
ZERO DETECT OUTPU
MANUAL
PRESET
MANUAL
RESET
COUNTER AT
PRESIGNAL VALUE
AUTOMATIC
PRESET
MAINSIGNAL OUTPUT
ZERO DETECT OUTPUT
COUNTER AT
MAINSIGNAL
NUMBER
COUNTER AT
ZERO
COUNTER AT
ZERO
FIGURE 2. AUTOMATIC OR MANUAL OPERATION IN UP MODE
FIGURE 3. AUTOMATIC OR MANUAL OPERATION IN DOWN MODE
COUNT INPUT
UP/ DOWN
TUDH
Tudh
Tdh
DIVIDE CONTROL
COUNT INHIBIT
Tds
Tcs
Tch
RESET
Trpw
INHIBIT
INTERNAL RESET
Tirh
PRESET ENABLE
Tppw
INHIBIT
Tiph
INTERNAL PRESET
MAINS IGNAL, PRES IGNAL,
ZERO DETECT OUTPUT
Tdo
Tdo
DATA TRANSFER
INPUT
Tdt h
SCAN CLOCK
INPUT
MSD OUTPUT
LSD + 4 OUTPUT
7 SEGMENTS
OUTPUTS
BCD OUTPUTS
Tgb
Tgb
STORAGE SELECT
INPUTS
BCD DATA
INPUT *
FIGURE 4 . TIMING DIAGRAM
* BCD dat a input assumed t o be applied from a set of t humbwheel swit ches as shown in Figure 5 .
7055-012703-4
LSI [ LSI COMPUTER SYSTEMS ]
