SC28C94 Philips Semiconductors, SC28C94 Datasheet - Page 29

• Manufacturer Part Number: SC28C94
• Description: Quad universal asynchronous receiver/transmitter QUART
• Manufacturer: Philips Semiconductors

Philips Semiconductors
1998 Aug 19
Quad universal asynchronous receiver/transmitter (QUART)
NOTE: I/O PIN DATA IS NOT LATCHED
I/O as Output
NOTES:
1. INCLUDES I/O WHEN USED AS TxRDY or RxDY/FFULL OUTPUTS AS WELL AS IRQN.
2. 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
SURES TRUE SWITCHING HAS OCCURRED. BEYOND THIS LEVEL, THE EFFECTS OF EXTERNAL CIRCUITRY AND TEST ENVIRONMENT ARE PRONOUNCED
AND CAN GREATLY AFFECT THE RESULTANT MEASUREMENT.
I/O as Input
WRN
RDN
CEN
I/O PINS MUST BE STABLE FOR NON-CHANGING BUS DATA DURING THE READ.
INTERRUPT
INTERRUPT
OUTPUT
OUTPUT
WRN
RDN
RESET
1
1
t
PS
OLD DATA
V
M
Figure 13. Interrupt Timing
t
Figure 12. I/O Port Timing
PD
Figure 11. Reset Timing
M
, TO A POINT 0.5V ABOVE V
t
IR
t
IR
t
29
RES
OL
. THIS POINT REPRESENTS NOISE MARGIN THAT AS-
t
PD
V
t
PH
OL
V
OL
+0.5V
SD00169
+0.5V
V
OL
NEW DATA
V
OL
Product specification
SC28C94
SD00170
SD00171