SAM-M10Q - Integration manual
The TIMEPULSE pin is shared with SAFEBOOT_N pin. If this pin is low at receiver startup,
the receiver enters safeboot mode. In normal operation, this pin is used for time pulse. Make
sure there is no load at this pin, which could cause the pin being low at startup.
2.3.3.4 EXTINT
SAM-M10Q supports external interrupts at the EXTINT pin. The EXTINT pin has a fixed input voltage
threshold with respect to V_IO. It can be used for functions such as accurate external
The EXTINT pin enables
for host-controlled on/off operation of the receiver, and as
a wake-up source for power save mode on/off operation (PSMOO). If configured for host-controlled
on/off operation, the internal pull-up is disabled. Make sure the EXTINT input is always driven within
the defined voltage level by the host.
The EXTINT pin can also be configured for another functionality.
EXTINT functionality is only available at the EXTINT pin.
2.3.3.5 TX_READY
The receiver has an internal message buffer for storing bytes to be sent to the host application.
TX-ready feature in TX_READY pin enables I2C to have an associated signal to indicate that the
buffer has bytes to be transmitted. The host application can wait on the signal instead of polling
the interface.
The TX-ready signal is enabled and assigned to a selected pin with CFG-TXREADY configuration
items. The polarity of the signal (active-low or active-high) and the threshold for amount of bytes in
the buffer must also be configured. When the number of bytes in the buffer reaches the threshold,
the TX-ready signal becomes active. The signal stays active until all of the bytes in the buffer have
been transferred. The receiver has additional small transmit buffer for each interface. Up to 16 bytes
may still need to be transferred to the host after the TX-ready signal has become inactive.
The TX-ready signal can be assigned to any pin. Old function on the pin must be disabled before the
assigment. Pin assignment can be verified with the UBX-MON-HW3 message.
The threshold value of the CFG-TXREADY-THRESHOLD is presented as 8-byte (64 bit) chunks.
Divide the desired threshold value by 8. E.g., value of 128 sets the TX-ready signal activation
threshold to 1024 bytes. The threshold should not be set above 2048 bytes (256 8-byte chunks).
Otherwise, the TX-ready signal may not be activated in time, and some messages may get
discarded.
2.3.3.5.1 Extended TX timeout
If the host does not communicate over I2C for more than 1.5 seconds, the receiver assumes that
the host is no longer using this interface and no more packets are scheduled for this interface.
This mechanism can be changed by enabling "extended TX timeouts" (configuration key CFG-I2C-
EXTENDEDTIMEOUT). When enabled, the receiver delays idling the interface until the allocated and
undelivered bytes for this interface reach 4 kB. This feature is especially useful when using the TX-
ready feature with a message output rate of less than once per second, and fetching data only when
available, determined by the TX_READY pin becoming active.
2.4 Forcing receiver reset
Typically in GNSS receivers, a distinction is made between cold, warm, and hot start based on the
type of valid information the receiver has at the time of the restart.
UBX-22020019 - R01
2 Receiver functionality
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