EP-P80P+
Page 10
Diagnostic Card Usage
7-Segment Decoder and Decimal Point (DP) Indicator
Within the circular trace buffer, the register contents of the
entry pointed by the read pointer (RP) are chosen for display.
The 8-bit binary contents are further divided into low and high
nibbles, 4 bits each. Alternate selection between both nibbles is
periodically conducted according to an internal multiplexed
timing clock. The selected nibble is then converted into segment
codes for digit display by the built-in BCD to 7-segment decoders.
The 7 segments are labeled a through g as shown below. Besides,
the decimal point segments of the display can be driven by the
multiplexed output DP to indicate current status of the read and
write pointers within the circular buffer. The coding of DP
display is shown in table 1.
h
g
i
H
-
P
D
w
o
L
-
P
D
s
u
t
a
t
S
ti
g
i
D
tf
e
L
ti
g
i
D
t
h
g
i
R
ff
O
ff
O
y
rt
n
e
t
s
e
t
a
L
n
O
n
O
y
rt
n
e
t
s
e
d
l
O
ff
O
n
O
p
e
t
s
e
n
o
d
r
a
w
r
o
F
n
O
ff
O
p
e
t
s
e
n
o
d
r
a
w
k
c
a
B
<Figure 3: Hexadecimal digital display and segment definition>
<Table 1: Decimal Pointer (DP) display decoder>