SC28L202 Philips Semiconductors, SC28L202 Datasheet - Page 70

• Manufacturer Part Number: SC28L202
• Description: Dual universal asynchronous receiver/transmitter DUART
• Manufacturer: Philips Semiconductors

Philips Semiconductors
2000 Feb 10
Dual UART
NOTES:
1.
2.
INTRN or OP3-OP7 when used as interrupt outputs.
The test for open-drain outputs is intended to guarantee switching of the output transistor. Measurement of this response is referenced from the midpoint of the switching
signal, V
test environment are pronounced and can greatly affect the resultant measurement.
C1 = C2
C1 and C2 should be chosen according to the crystal manufacturer’s specification.
C1 and C2 values will include any parasitic capacitance of the wiring and X1 X2 pins.
Package capacitance approximately 4pF.
X1/CLK
CTCLK
M
RxC
TxC
, to a point 0.5V above V
24pF FOR C
L
= 20pF
PARASITIC CAPACITANCE
PARASITIC CAPACITANCE
OL
INTERRUPT
INTERRUPT
. This point represents noise margin that assures true switching has occurred. Beyond this level, the effects of external circuitry and
t
t
t
t
CLK
CTC
Rx
Tx
OUTPUT
OUTPUT
3pF
3pF
C2
C1
WRN
RDN
1
1
Figure 8. Interrupt Timing (80xxx mode)
14.7456MHz
t
t
t
t
Figure 9. Clock Timing
CLK
CTC
Rx
Tx
X1
X2
V
M
64
4pF
2pF
t
IR
V
*NOTE: X2 MUST BE LEFT OPEN.
CLK
M
NOTE:
RESISTOR REQUIRED
FOR TTL INPUT.
SC28L92
50k
to
100k
t
IR
V
OL
V
OL
+0.5V
+0.5V
V
OL
V
V
CC
OL
470
Objective specification
SC28L202
X2*
TO UART
CIRCUIT
X1
SD00689
SD00136