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S-MOS Systems, Inc. 2460 North First Street San Jose, CA 95131 Tel: (408) 922-0200 Fax: (408) 922-0238
268-0.4
21
2.4 – 2.4.3
2.0 Pin Description
2.4 Pin Functions
2.4.1 Power Supply
Pin Name
Function
V
DD
4.5 to 5.5V (SED1330F), 3.0 to 5.5V (SED1336F) or 2.7 to 5.5V (SED1330F/1335F) supply.
This may be the same supply as the controlling microprocessor.
Ground
V
SS
Note:
The peak supply current drawn by the SED1330F/1335F/1336F may be up to ten times the average supply current. The power
supply impedance must be kept as low as possible by ensuring that supply lines are sufficiently wide and by placing 0.47
μ
F
decoupling capacitors that have good high-frequency response near the device’s supply pins.
2.4.3 Microprocessor Interface
Pin Name
D0 to D7
Function
Tristate input/output pins. Connect these pins to an 8- or 16-bit microprocessor bus.
Microprocessor interface select pin. The SED1336F supports both 8080 family processors
(such as the 8085 and Z80) and 6800 family processors (such as the 6802 and 6809).
SEL1*
0
1
SEL2
0
0
Interface
8080 family
6800 family
A0
A0
A0
RD
RD
E
WR
WR
R/W
CS
CS
CS
* SED1330F and SED1335F only
Note:
SEL1 should be tied directly to V
DD
or V
SS
to prevent noise. If noise does appear on SEL1, decouple it to ground using a
capacitor placed as close to the pin as possible.
SEL1, SEL2
2.4.2 Oscillator
Pin Name
Function
(OSC) XG
Crystal connection for internal oscillator (see Section 8.3). This pin can be driven by an external
clock source that satisfies the timing specifications of the EXT
φ
0 signal (see Section 4.3.6).
Crystal connection for internal oscillator. Leave this pin open when using an external clock
source.
Clock output (SED1336F only). Same phase as XG. Clock is output when system command
P1 is executed. Output stops during system reset.
(OSC2) XD
CLO