Philips Semiconductors
Dual asynchronous receiver/transmitter (DUART)
Product data
SCC2681T
RDN
tPS
IP0–IP6
WRN
OP0–OP7
tPH
(a) INPUT PINS
tPD
OLD DATA
(b) OUTPUT PINS
Figure 5. Port Timing
NEW DATA
SD00101
WRN
VM
INTERRUPT1
OUTPUT
tIR
VOL +0.5V
VOL
NOTES:
1. INTRN or OP3-OP7 when used as interrupt outputs.
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, VM, to a point 0.5V above VOL. This point represents noise margin that assures true switching has occurred. Beyond this level, the effects of external circuitry and
test environment are pronounced and can greatly affect the resultant measurement.
SD00102
Figure 6. Interrupt Timing
2004 Apr 06
10