Ublox TOBY-R2 Series System Integration Manual

Also see for TOBY-R2 Series: User guide

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Ublox TOBY-R2 Series System Integration Manual Manual pdf 27 page image

TOBY-R2 series - System integration manualUBX-16010572 - R10 System description Page 27 of 151Figure 14 shows the module switch-on sequence from the not-powered mode, describing the followingphases: The external supply is applied to the VCC module supply inputs, representing the start-up event. The V_BCKP RTC supply output is suddenly enabled by the module as VCC reaches a valid voltagevalue. The PWR_ON and the RESET_N pins suddenly rise to high logic level due to internal pull-ups. All the generic digital pins of the module are tri-stated until the switch-on of their supply source(V_INT). The internal reset signal is held low: the baseband core and all the digital pins are held in the resetstate. The reset state of all the digital pins is reported in the pin description table of TOBY-R2series data sheet [1]. When the internal reset signal is released, any digital pin is set in a proper sequence from the resetstate to the default operational configured state. The duration of this pins’ configuration phasediffers within generic digital interfaces and the USB interface due to host / device enumerationtimings (see section 1.9.2). The module is fully ready to operate after all interfaces are configured.VCCV_BCKPPWR_ONRESET_NV_INTInternal ResetSystem StateBB Pads State Internal Reset → Operational OperationalTristate / Floating Internal ResetOFF ONStart of interfaceconfigurationModule interfacesare configuredStart-upeventFigure 14: TOBY-R2 series switch-on sequence descriptionThe greeting text can be activated by means of +CSGT AT command (see u-blox AT commandsmanual [2]) to notify the external application that the module is ready to operate (i.e. ready to reply toAT commands) and the first AT command can be sent to the module, given that autobauding has tobe disabled on the UART to let the module sending the greeting text: the UART has to be configuredat fixed baud rate (the baud rate of the application processor) instead of the default autobauding,otherwise the module does not know the baud rate to be used for sending the greeting text (or anyother URC) at the end of the internal boot sequence.☞ The Internal Reset signal is not available on a module pin, but the host application can monitor theV_INT pin to sense the start of the TOBY-R2 series module switch-on sequence.☞ Before the switch-on of the generic digital interface supply source (V_INT) of the module, novoltage driven by an external application should be applied to any generic digital interface of themodule.☞ Before the TOBY-R2 series module is fully ready to operate, the host application processor shouldnot send any AT command over the AT communication interfaces (USB, UART) of the module.☞ The duration of the TOBY-R2 series modules’ switch-on routine can vary depending on theapplication / network settings and the concurrent module activities.