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GM862-GPS Hardware User Guide
1vv0300728 Rev. 0 - 27/04/06
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Right reserved page 24 of 55
NOTE: The UART input line TXD (rx_uart) of the GM862-GPS is NOT internally pulled up with a resistor, so there
may be the need to place an external 47KΩ pull-up resistor, either the DTR (dtr_uart) and RTS (rts_uart) input lines
are not pulled up internally, so an external pull-up resistor of 47KΩ may be required.
A power source of the internal interface voltage corresponding to the 2.8VCMOS high level is
available at the PWRCTL pin on the connector, whose absolute maximum output current is 10mA.
A maximum of 9 47 KΩ pull-up resistors can be connected to the PWRCTL pin, provided no other
devices are connected to it and the pulled-up lines are GM862-GPS input lines connected to open
collector outputs in order to avoid latch-up problems on the GM862-GPS.
Care must be taken to avoid latch-up on the GM862-GPS and the use of this output line to power
electronic devices shall be avoided, especially for devices that generate spikes and noise such as
level translators, digital ICs or microcontrollers, failure in any of these condition can severely
compromise the GM862-GPS functionality.
NOTE: The input lines working at 2.8VCMOS can be pulled-up with 47KΩ resistors that can be connected directly to
the PWRCTL line provided they are connected as in this example.
NO OTHER devices should be powered with the PWRCTL line, otherwise the module functionality may be
compromised.