ENABLE
The
SP211E
and
SP213E
all feature an enable
input, which allows the receiver outputs to be
either tri–stated or enabled. This can be especially
useful when the receiver is tied directly to a
microprocessor data bus. For the
SP211E,
enable
is active low; that is, 0V applied to the ENABLE
pin will enable the receiver outputs. For the
SP213E,
enable is active high; that is, +5V
applied to the ENABLE pin will enable the
receiver outputs.
SD
0
0
1
1
SP213E Only Power
EN SD
EN
Up/Down
0
1
1
Up
1
0
1
1
0
0
0
1
0
Up
Down
Down
Receiver
Outputs
Enable
Tri–state
Enable
Tri–state
Table 2. Wake–Up Truth Table
POWER UP WITH SD ACTIVE (Charge pump in shutdown mode)
t
0 (POWERUP)
+5V
R
OUT
DATA VALID
0V
t
WAIT
ENABLE
SD
DISABLE
POWER UP WITH SD DISABLED (Charge pump in active mode)
t
0 (POWERUP)
+5V
R
OUT
DATA VALID
0V
t
ENABLE
ENABLE
SD
DISABLE
EXERCISING WAKE–UP FEATURE
t
0 (POWERUP)
+5V
R
OUT
DATA VALID
0V
t
ENABLE
SD
DISABLE
t
WAIT
V
CC
= +5V ±10%; T
A
= 25°C
t
WAIT
= 2ms typical, 3ms maximum
t
ENABLE
= 1ms typical, 2ms maximum
Figure 6. Wake–Up Timing
SP207EDS/09
SP207E Series High Performance RS232 Transceivers
© Copyright 2000 Sipex Corporation
DATA VALID
t
ENABLE
ENABLE
DATA VALID
t
ENABLE
DISABLE
8
SIPEX [ SIPEX CORPORATION ]
