Datasheet

MAX5580–MAX5585
Buffered, Fast-Settling, Quad,
12-/10-/8-Bit, Voltage-Output DACs
30 ______________________________________________________________________________________
GPI, GPOL, GPOH
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
(RTP1 and RTP2).
2) Detect whether a falling edge has occurred since
the last read or reset (LF1 and LF2).
3) Detect whether a rising edge has occurred since
the last read or reset (LR1 and LR2).
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 22.
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.
GPOL outputs a constant low, and GPOH outputs a
constant high. See Figure 6.
TOGG
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).
FAST
The MAX5580–MAX5585 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–SPDD bit settings.
Table 22. GPI Read Command
DATA CONTROL BITS DATA BITS
DIN1111001XXXXXXXXX
DOUTRB X X XXXXXXXXRTP2 LF2 LR2 RTP1 LF1 LR1
Table 23. Unipolar Code Table (Gain = +1)
DAC CONTENTS
MSB LSB
ANALOG OUTPUT
1111 1111 1111 +V
REF
(4095 / 4096)
1000 0000 0001 +V
REF
(2049 / 4096)
1000 0000 0000 +V
REF
(2048 / 4096) = V
REF
/ 2
0111 1111 1111 +V
REF
(2047 / 4096)
0000 0000 0001 +V
REF
(1 / 4096)
0000 0000 0000 0
MAX5580
DAC_
REF
OUT_
V
OUT_
= V
REF_
x CODE / 4096
WHERE CODE IS THE DAC INPUT
CODE (0 TO 4095 DECIMAL)
MAX6126
Figure 7. Unipolar Output Circuit
X = Don’t care.