NEO-8Q / NEO-M8 - Hardware integration manual
UBX-15029985 - Production information
Hardware description
Page 8 of 9
C1-Public
For more information about the DDC implementation, see the u-blox 8 / u-blox M8 Receiver
Description Including Protocol Specification [4]. For bandwidth information, see the corresponding
product data sheet. For timing parameters, consult the I2C-bus specification [7].
☞
The NEO-8Q and NEO-M8 series DDC interface supports serial communication with most u-blox
cellular modules. See the specification of the applicable cellular module to confirm compatibility.
1.4.4
SPI
An SPI interface is available for communication to a host CPU.
☞
SPI is not available in the default configuration, because its pins are shared with the UART and
DDC interfaces. The SPI interface can be enabled by connecting
D_SEL
to ground. For speed and
clock frequency, see the corresponding product data sheet.
1.4.5
TX_READY
The
TX_READY
function is used to indicate when the receiver has data to transmit. A listener can wait
on the
TX_READY
signal instead of polling the DDC or SPI interfaces. The UBX-CFG-PRT message lets
you configure the polarity and the number of bytes in the buffer before the TX READY signal goes
active. The
TX_READY
function can be mapped to
TXD
(PIO 06). The
TX_READY
function is disabled
by default.
☞
The
TX_READY
functionality can be enabled and configured by AT commands sent to the u-blox
cellular module supporting the feature. For more information, see the GPS Implementation and
Aiding Features in u-blox wireless modules [8].
1.5
I/O pins
All I/O pins make use of internal pull-ups. Thus, there is no need to connect unused pins to VCC_IO.
1.5.1
RESET_N: Reset
Driving
RESET_N
low activates a hardware reset of the system. Use this pin only to reset the module.
Do not use
RESET_N
to turn the module on and off, since the reset state increases power
consumption. With NEO-8Q and NEO-M8 series modules
RESET_N
is an input only.
☞
The RTC time is also reset (but not BBR).
1.5.2
EXTINT: External interrupt
EXTINT (EXTINT0
on
NEO-M8T), PIO 13
is an external interrupt pin with fixed input voltage
thresholds with respect to
VCC
(see the corresponding product data sheet for more information). It
can be used for wake-up functions in power save mode on NEO-8Q and NEO-M8 series modules and
for aiding. Leave open if unused. The function is disabled by default.
If the
EXTINT
is not used for an external interrupt function, it can be used for some other purpose. For
example, as an output pin for the
TX_READY
feature to indicate that the receiver has data to
transmit.
EXTINT1
is an external interrupt pin on
NEO-M8T
with fixed input voltage thresholds with respect to
VCC
(see the corresponding product data sheet for more information). It can be used for wake-up
functions in Power Save Mode on NEO-M8T module and for aiding. Leave open if unused. The function
is disabled by default.
