max5591 Maxim Integrated Products, Inc., max5591 Datasheet - Page 29

• Manufacturer Part Number: max5591
• Description: Buffered, Fast-settling, Octal, 12/10/8-bit, Voltage-output Dacs
• Manufacturer: Maxim Integrated Products, Inc.

UPIO1 and UPIO2 can each be configured as a gener-
al-purpose input (GPI), a general-purpose output low
(GPOL), or a general-purpose output high (GPOH).
The GPI can serve to detect interrupts from µPs or micro-
controllers. The GPI has three functions:
1) Sample the signal at GPI at the time of the read
2) Detect whether or not a falling edge has occurred
3) Detect whether or not a rising edge has occurred
RTP1, LF1, and LR1 represent the data read from
UPIO1; RTP2, LF2, and LR2 represent the data read
from UPIO2.
To issue a read command for the UPIO configured as
GPI, use the command in Table 23.
Once the command is issued, RTP1 and RTP2 provide
the real-time status (0 or 1) of the inputs at UPIO1 or
UPIO2, respectively, at the time of the read. If LF2 or
LF1 is one, then a falling edge has occurred on the
respective UPIO1 or UPIO2 input since the last read or
reset. If LR2 or LR1 is one, then a rising edge has
occurred since the last read or reset.
Table 23. GPI Read Command
X = Don’t care.
Table 24. Unipolar Code Table (Gain = +1)
DOUTRB
DATA
MSB
1111
1000
1000
0111
0000
0000
DIN
(RTP1 and RTP2).
since the last read or reset (LF1 and LF2).
since the last read or reset (LR1 and LR2).
DAC CONTENTS
1111
0000
0000
1111
0000
0000
1
X
CONTROL BITS
Buffered, Fast-Settling, Octal, 12/10/8-Bit,
______________________________________________________________________________________
0
X
1111
0001
0000
1111
0001
0000
LSB
1
X
+V
REF
1
X
+V
+V
+V
ANALOG OUTPUT
(2048 / 4096) = V
+V
REF
REF
REF
GPI, GPOL, GPOH
REF
(4095 / 4096)
(2049 / 4096)
(2047 / 4096)
1
X
(1 / 4096)
0
X
0
REF
X
1
/ 2
X
X
GPOL outputs a constant low, and GPOH outputs a
constant high. See Figure 6.
Use the TOGG input to toggle the DAC outputs
between the values in the input registers and DAC reg-
isters. A delay of greater than 100ns from the end of the
previous write command is required before the TOGG
signal can be correctly switched between the new
value and the previously stored value. When TOGG =
0, the output follows the information in the input regis-
ters. When TOGG = 1, the output follows the informa-
tion in the DAC register (Figure 5).
The MAX5590–MAX5595 have two settling-time-mode
options: FAST (3µs max) and SLOW (6µs max). To
select the FAST mode, drive FAST low, and to select
SLOW mode, drive FAST high. This overrides (not over-
writes) the SPDA–SPDH bit settings.
Figure 7. Unipolar Output Circuit
REF_
Voltage-Output DACs
X
X
MAX5590
DATA BITS
DAC_
X
X
RTP2
X
LF2
X
LR2
X
V
CODE IS THE DAC_ INPUT
CODE (0 TO 4095 DECIMAL).
OUT_
RTP1
OUT_
X
= V
REF_
x CODE / 4096
LF1
X
TOGG
FAST
LR1
X
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