5.1.1
FIRMWARE DOWNLOAD PORT
JP2 is a firmware download port and is used during production to download firmware into the
processor’s flash memory. Once programmed the 3 jumpers are installed linking 1-2, 3-4 & 5-6 for
normal operation. For upgrades the links are removed and new firmware is loaded via JP2 using the
appropriate interface hardware.
5.1.2
RS232 & 5VTTL SERIAL INTERFACE
The URT500 serial port can be programmed to operate at speeds from 150 – 38400bps and is used to
program the modem, control the modem during testing and for transferring data over the radio link
when in operation.
Internal links can be set to provide full RS232 or 5V TTL signal levels, either mode can be run true or
inverted. Unless otherwise specified the product is shipped set for “True RS232” operation. Should
these parameters need to be changed, the following can be used as a guide.
+
1
1
1
1
1
1
1
JP6
JP6
JP6
JP6
JP5
JP5
JP5
JP2
JP2
1
1
Link 2-3
RS232 without DTR shutdown
Link 1-2
RS232 with DTR shutdown
Link 4-5
5V TTL
Link 2-3 (or No Links)
Inverted Signal
Link 1-2
Non-Inverted Signal
JP3
Link
1-2
3-4
5-6
for
normal
operation
JP6 - RS232/TTL SELECTION
JP5 - INVERSION SELECTION
JP2 - FIRMWARE PORT
Note: the –5V generator for the RS232 interface is turned off if 5VTTL is selected, and also while DTR
is inactive if the DTR shutdown link option is enabled. The latter option is complemented by the
software DTR shutdown option which causes the processor to shut down all the radio circuits while
DTR is inactive. For lowest current consumption both options must be enabled.
URT500 Manual
Page 15 of 42
Rev. C – 6 August 2008