User Manual

Table Of Contents
Hardware Interfaces
20 Hardware Overview
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 (pin 15) line is configured as an input. The input value will
determine whether the Boot Loader
will wait for user commands or immediately load the
Application Firmware
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).