Globalstar ST150M User Manual page 56

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9.1.6.2 Preemption by Priority
In the event the queue is full, the oldest message found at the lowest priority that can be aborted will be removed from the
send queue to make room for the next incoming message. If no lower priority messages are found, an error will be returned.
9.1.6.3 Preemption by Time and Priority
In the event the queue is full, the oldest message with lowest priority found that can be aborted will be removed to make
room for the next incoming message.
9.1.6.4 OTA Message Logging
All messages that are added to the transmit queue are logged into device flash for diagnostic retrieval. These entries contain
information about the message, which includes timestamp, message UMN (unique message number), message size, and
any flags that indicate a transmission failure. Transmission failures can occur due to reasons defined in the Transmitter
section, or due to a message being aborted or pre-empted.
9.1.6.5 Transmit Queue Events
Transmit Queue events can be sent via URCs to indicate asynchronous events that are occurring, and can be very useful for
debugging.
9.1.7 GPIO
Available GPIOs can be setup for inputs, module event interrupt outputs, special input functions, or for supported peripheral
usage.
9.1.7.1 Reserved vs Non-Reserved GPIO Entries
Once a GPIO is assigned to a role, it is considered reserved. A reserved GPIO cannot be assigned to another role without
being un-reserved first
9.1.7.2 Inputs
When a GPIO is setup as an input, the GPIO component will generate events on edge transitions.
9.1.7.3 Event Interrupts
When a GPIO is setup as an Event Interrupt, the corresponding pin can be shared amongst other module IRQs as long as the
active high/low polarity is the same.
This feature makes it possible to have module interrupts assert and wake an external MCU or device. Each event that
generates an interrupt can be read via the Interrupt AT command and doing so will also clear all active interrupts.
9.1.8 SPECIAL FUNCTION INPUTS
Special Function Inputs make it possible to add device-specific features in the application and will send events that describe
input transitions for these features. These functions include the following, and can be mapped to Software Inputs 1-8 (See
Inputs section):
9.1.8.1 Tamper Detection
Used to trigger a tamper event
9.1.8.2 Line Power Detection
Used for line-power detection status. Line Power status is described in the monthly Health Check OTA message, but can also
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