MAX11311 Datasheet, PDF (28/51 Pages) Maxim Integrated Products – PIXI, 12-Port Programmable Mixed-Signal I/O with 12-Bit ADC, 12-Bit DAC, Analog Switches, and GPIO

MAX11311
PIXI, 12-Port Programmable Mixed-Signal I/O with
12-Bit ADC, 12-Bit DAC, Analog Switches, and GPIO
not masked. By default, all interrupts are masked upon
power-up or reset. The interrupts are listed hereafter.
The ADCFLAG (ADC Flag) interrupt indicates that the
ADC just completed a conversion or set of conversions.
It is asserted either at the end of a conversion when the
ADC is in single-conversion mode or at the end of a
sweep when the ADC is either in single-sweep mode or
continuous-sweep mode. ADCFLAG is cleared when the
interrupt register is read.
The ADCDR (ADC Data Ready) interrupt is asserted
when at least one ADC data register is refreshed. Since
one conversion per ADC-configured port is performed
per sweep, many sweeps may be required before refreshing
the data register of a given ADC-configured port that
utilizes the averaging function. See the ADC Averaging
Function section. To determine which ADC-configured
port received a new data sample, the host must read
the ADC status registers. ADCDR is cleared after the
interrupt register and both ADC status registers are read
subsequently.
The ADCDM (ADC Data Missed) interrupt is asserted when
any ADC data register is not read by the host before new
data is stored in that ADC data register. ADCDM is cleared
after the interrupt register is read.
The GPIER (GPI Event Received) interrupt indicates that
an event has been received on one of the GPI-configured
ports. Each GPI port can be configured to generate an
interrupt for an event such as detecting a rising edge, a
falling edge, or either edge at the corresponding port. If
the GPI port is configured to detect no edge, it is equivalent
to masking the interrupt related to that port. A GPI status
register allows the host to identify which port detected the
event. GPIER is cleared after the interrupt register and
both GPI status registers are read subsequently.
The GPIEM (GPI Event Missed) interrupt informs the
host that it did not service the GPI interrupt caused by the
occurrence of an event recorded by GPI status registers
before another event was received on the same port. The
host must read the interrupt register and the GPI status
registers whenever a GPI event received interrupt occurs;
otherwise, the GPIEM register is asserted upon receiving
the next event. This interrupt must be used in conjunction
with the GPIER interrupt bit to operate properly. GPIEM
is cleared after the interrupt register and both GPI status
registers are read subsequently.
The DACOI (DAC Overcurrent) interrupt indicates that
a DAC-configured port current exceeded approximately
50mA. This limit is not configurable. A DAC overcurrent
status register allows the host to identify which DAC-
configured port exceeded the 50mA current limit. DACOI
is cleared after the interrupt register is read, and both
DAC overcurrent status registers are read subsequently.
The TMPINT[2:0] (Internal Temperature Monitor)
interrupt has three sources of interrupt, each independently
controllable: a new internal temperature value is ready, the
internal temperature value exceeds the maximum limit, or
the internal temperature value is below the minimum limit.
TMPINT is cleared after the interrupt register is read.
The TMPEXT1[2:0] (1st External Temperature Monitor)
interrupt has three sources of interrupt, each independently
controllable: a new first external temperature value is
ready, the first external temperature value exceeds the
maximum limit, or the first external temperature value is
below the minimum limit. TMPEXT1 is cleared after the
interrupt register is read.
The TMPEXT2[2:0] (2nd External Temperature Monitor)
interrupt has three sources of interrupt, each independently
controllable: a new second external temperature value is
ready, the second external temperature value exceeds
the maximum limit, or the second external temperature
value is below the minimum limit. TMPEXT2 is cleared
after the interrupt register is read.
The VMON (High-Voltage Supply Monitor) interrupt is triggered
when AVDDIO supply voltage falls below approximately
4V. VMON is cleared after the interrupt register is read.
Temperature Sensors Overview
The MAX11311 integrates one internal and two external
temperature sensors. The external sensors are diode-
connected transistors, typically a low-cost, easily mounted
2N3904 NPN type, that replace conventional thermis-
tors or thermocouples. The external sensors’ accuracy is
typically ±1°C over the -40°C to +150°C temperature range
with no calibration necessary. Use of a transistor with a
different ideality factor produces a proportionate difference
in the absolute measured temperature. Parasitic series
resistance results in a temperature reading error of about
0.25°C per Ohm of resistance. The MAX11311 features a
series resistance cancellation mode (RS_CANCEL) that
eliminates this error for resistances up to 10 Ohms. The
external sensors can also measure the die temperature
of other ICs, such as microprocessors, that contain a substrate-
connected diode available for temperature-sensing
purposes. Temperature data can be read from the
temperature data registers. The temperature data
format is in two’s complement, with one LSB representing
0.125°C.
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