Tempo Display - Roland CR-5000 Service Notes

^PD8048C
CR-8000only
PIN NAKE
T0
Tl
INT
DATA BUS
PIN
NO.
39
PORT
1
?10
Pll
P12
P13
?14
P15
P16
?17
12
13
14
15
16-19
rUKCTION
NO APPLICATION
(KEPT LOW)
TEMPO CLOCK
IN
START/STOP SIGNAL
IN
POST
2
P20-P23
P24
P25
?26
P27
27
28
29
30
31
32
33
34
KEPT HIGH
KEPT LOV
KEPT LOV
KEPT LOV
NO CONNECT
ION
for Internal
program
initialization
21-24
35
36
37
35
7-SEGMENT
LED LIGHT
SIGNAL
OUTPUTS
NO CONNECTION
NO CONNECTION
(NOT IN USE)
7-SE3KENT LED
CONTROL
SIGNAL
OUTPUT
CR-5000/8000
TEMPO DISPLAY
(CR-8000 only)
UPD8048C
IC3 on
Control Brd counts
Tempo Clocks derived from Q9
on
CPU Brd whenever power
is
being
fed to the CR-8000.
Since
24
tempo clocks are made
equal
to one
J,
actual tempo dis-
played
is
clocks per minute
24
CPU performs
an equivalent
eq
.
in a short period and drives
Q18-Q20
on Control
Brd in
syn-
chronous with drive signals for
7
segments
of
display LEDs.
Upon rhythm running
INT of
CPU
IC3
goes and stays negative with
which CPU's internal
count gate
is
disabled, then re-started
at the first falling edge of the
next tempo clock.
This count
break allows CPU
to
skip tran-
sitional tempo clock
that
is
reset by
a
start signal.
If INT remains high after
rhythm running, tempo display
varies temporarily.