Pin name
Description
D/C
Data/Control Select (Input)
This signal defines the type of information
transferred to or from the SCC. A High means data
is transferred; a Low indicates a command is
transferred.
Data Bus
D7-D0
Data Bus (Input/Output; Three State)
Three lines carry data and commands to and from
the SCC.
Interrupt
IEI
Interrupt Enable In (Input; Active High)
IEI is used with IEO to from interrupt daisy chain
when there is more than one interrupt-driven
device. A High IEI indicates that no other higher
priority device has an interrupt under service or is
requesting an interrupt.
IEO
Interrupt Enable Out (Output; Active High)
IEO is High only if IEI is High and the CPU is not
servicing an SCC interrupt or the SCC is not
requesting an interrupt (interrupt acknowledge
cycle only). IEO is connected to the next lower
priority device’s IEI input and thus inhibits interrupts
from lower priority devices.
INT
Interrupt Request (Output; Active Low, Open
Drain)
This signal is activated when the SCC requests an
interrupt.
INTACK
Interrupt Acknowledge (Input; Active Low)
This signal indicates an active interrupt
acknowledge cycle. During this cycle, the SCC
interrupt daisy chain is determined. When RD
becomes active. the SCC interrupt daisy chain
settles. When RD becomes active, the SCC places
an interrupt vector on the data bus (if IEI is High).
INTACK is latched by the rising edge of PCLK.
Serial Data
RxDA,
RxDB
Receive Data (Inputs; Active High)
These input signals receive serial data at standard
TTL levels.
TxDA, TxDB
Transmit Data (Outputs; Active High)
These output signals transmit serial data at
standard TTL levels.
Miscellaneous
GND
Ground
PCLK
Clock (Input)
This is the master SCC clock used to synchronize
internal signals. PCLK is not required to have any
phase relationship with the master system clock.
PCLK is a TTL-level signal. Maximum transmit rate
is 1/4 PCLK.
Vcc
+5 V Power Supply
f. 20 BIT BUFFERS
I.
FUNCTIONAL BLOCK DIAGRAM
II.
PIN CONFIGURATIONS
III.
PIN DESCRIPTION
Pin Names
Description
xOEx
Output Enable Inputs (Active LOW)
xAx
Data Inputs
xYx
3-State Outputs
IV.
FUNCTION TABLE(1)
Inputs
Outputs
xOE
1
xOE
2
xAx
xYx
L
L
L
L
L
L
L
H
H
X
X
Z
X
H
X
Z
NOTE: 1. H = HIGH Voltage level
L = LOW Voltage level
X = Don’t Care
Z = High Impedance
1LE
1O1
TO 9 OTHER CHANNELS
1D1
1OE
D
C
2LE
2O1
TO 9 OTHER CHANNELS
2D1
2OE
D
C
1OE
1
1LE
48
1O1
2
1D1
47
1O2
3
1D2
46
GND
4
GND
45
1O3
5
1D3
44
1O4
6
1D4
43
VCC
7
VCC
42
1O5
8
1D5
41
1O6
9
1D6
40
GND
10
GND
39
1O7
11
1D7
38
1O8
12
1D8
37
2O1
13
2D1
36
2O2
14
2D2
35
GND
15
GND
34
2O3
16
2D3
33
2O4
17
2D4
32
VCC
18
VCC
31
2O5
19
2D5
30
2O6
20
2D6
29
GND
21
GND
28
2O7
22
2D7
27
2O8
23
2D8
26
2OE
24
2LE
25
SO48-1
SO48-2
SSOP
TSSOP
TOP VIEW
SHARP SERVICE MANUAL JX8200SM [13] ELECTRICAL SECTION
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