GE864-QUAD Automotive V2 Hardware User Guide
1vv0300840 Rev.0.1 24/11/09
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved
page 39 of 65
NOTE: The UART input line TXD (rx_uart) of the GE864-QUAD Automotive V2 is NOT internally pulled up with a
resistor, so there may be the need to place an external 47K
Ω
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 47K
Ω
may be required.
A power source of the internal interface voltage corresponding to the 2.8VCMOS high level is
available at the PWRMON pin on the connector, whose absolute maximum output current is 1mA.
A maximum of 9 resistors of 47 K
Ω
pull-up can be connected to the PWRMON pin, provided no other
devices are connected to it and the pulled-up lines are GE864-QUAD Automotive V2 input lines
connected to open collector outputs in order to avoid latch-up problems on the GE864-QUAD
Automotive V2.
Care must be taken to avoid latch-up on the GE864-QUAD Automotive V2 and the use of this output
line to power electronic devices shall be avoided, especially for devices that generate spikes and
noise such as switching level translators, micro controllers, failure in any of these condition can
severely compromise the GE864-QUAD Automotive V2 functionality.
NOTE: The input lines working at 2.8VCMOS can be pulled-up with 47K
Ω
resistors that can be connected directly to
the PWRMON line provided they are connected as in this example.
NO OTHER devices than those suggested should be powered with the PWRMON line; otherwise the module
functionality may be compromised.
It is important to consider that the added circuit must have consumption lower than 1mA.
In case of reprogramming of the module has to be considered the use of the RESET line to start correctly the
activity.
The preferable configuration is having an external supply for the buffer.
