Configuring gpio settings, Reset line – ThingMagic Micro Hardware User Manual

Page 25

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and individually pulled externally to either high or low logic level, module power
consumption is as listed in the

Micro Power Consumption

table.

GPIOs may be reconfigured individually after power up to become outputs. This
configuration takes effect either at API execution or a few tens of milliseconds after power
up if the configuration is stored in nonvolatile memory. The configuration to outputs is
defeated if the module is held in the boot loader by

Reset Line

being held low. Lines

configured as outputs consume no excess power if the output is left open. Specified
module power consumption is achieved for one or more GPIO lines set as output and left
open. Users who are not able to provide external pull ups or pull downs on any given
input, and who do not need that GPIO line, may configure it as an output and leave it
open to achieve specified module power consumption.

Configuring GPIO Settings

The GPIO lines are configured as inputs or outputs through the MercuryAPI by setting the
reader configuration parameters /reader/gpio/inputList and /reader/gpio/outputList. Once
configured as inputs or outputs the state of the lines can be Get or Set using the gpiGet()
and gpoSet() methods, respectively. See the language specific reference guide for more
details.

Reset Line

Upon power up the RESET line is configured as an input. The input value will determine
whether the

Boot Loader

(pulled LOW) will wait for user commands or immediately load

the

Application Firmware

(left open) image and enter application mode. After that action is

completed, this line is configured as an output line. While the unit continues to be in
bootloader the line is driven high.

Once in application mode, the RESET line is driven low. if the module returns to the
bootloader mode, either due to an assert or “boot bootloader”, the RESET line will again
be driven high.

To minimize power consumption in the application, the RESET line should be either left
open or pulled weakly low (10k to ground).

See Note about baud rate applicable when using

TTL Level UART Interface

.

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