MAX11301 Datasheet, PDF (47/55 Pages) Maxim Integrated Products – Programmable Sample Averaging Per ADC Port

MAX11301
PIXI, 20-Port Programmable Mixed-Signal I/O with
12-Bit ADC, 12-Bit DAC, Analog Switches, and GPIO
Port Configuration Registers (Read/Write) (continued)
BIT
FIELD NAME
DESCRIPTION
• 1001: Mode 9 - Negative analog input to differential ADC
• The port is configured as a differential ADC negative input.
• The number of samples to average is defined by the associated positive port. The
functional parameters AVR and RANGE must be identical to those used by the
corresponding positive port.
• A port configured in mode 9 can be associated to more than one port configured in
mode 8.
• Functional parameters to be set: AVR, RANGE
• 1010: Mode 10 - Analog output for DAC and negative analog input to differential ADC
(Figure 4)
• While this port drives the voltage corresponding to its DAC data register, it also
operates as the negative input for the ADC.
• The number of samples to average is defined by the associated positive port. The
functional parameters AVR and RANGE must be identical to those used by the
corresponding positive port.
• A port configured in mode 10 can be associated to more than one port configured in
mode 8.
• When the ADC input voltage range is set from 0V to 2.5V (RANGE = 100 or 110), the
DAC data register value must be limited to the range of values corresponding to 0V
to 2.5V at the port. Internally, the DAC data register value is clipped, so that the PIXI
port voltage is contained within a range from 0V to 5V to prevent device damage.
• Functional parameters to be set: AVR, RANGE
• 1011: Mode 11 - Terminal to GPI-controlled analog switch (Figure 11)
• In this mode, two adjacent ports can be connected together through an analog
switch controlled by a GPI-configured port (designated by the functional parameter
ASSOCIATED PORT). This function involves three ports. The switch controlling port
needs to be separately configured in GPI mode. Only the port with the lower index
needs to be configured in mode 11. The port with the higher index can be configured
in any other mode, except mode 2. If the port of higher index operates in an ADC-
related mode (mode 6, 7, 8, or 9), the signals applied to the port in mode 11 must
comply with the input voltage range for which the port of higher index is configured.
• Port 19 cannot be configured in mode 11, as there is no switch between ports 0and
19.
• Functional parameters to be set: INV, ASSOCIATED PORT
• 1100: Mode 12 - Terminal to register-controlled analog switch
• This mode is identical to Mode 11, except that the switch remains closed as long as this
port is configured in mode 12.
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