UM1015
Switch and jumper settings
Doc ID 18124 Rev 1
17/38
4.3 Jumpers
and
connectors
The jumpers and connectors numbered below refer to the CPU board schematics (available
on
www.st.com/spear
).
Sheet 4
●
Connector J3 is a standard 20-pin 2.54 mm connector used for JTAG connections.
●
Jumper J5 enables the power supply to the Real Time Clock block.
If jumper J5 is closed, the RTC is powered (standard).
●
Connector J10 is a 2 vie 1.25 mm pitch connector for battery back-up with cable.
Sheet 5
●
Connector J11 is a standard power connector for the ADC power supply with a 2.1-mm
central pitch.
Sheet 6
●
Jumpers J6, J7, J8 and J9 are serial jumpers for the SPEAr power rail.
All jumpers MUST be closed. This configuration is used for power measurements.
Sheet 7
●
Jumper J22 is a 4-pin symmetric IDC (or strip) connector that switches RX and TX
signals for different types of RS-232 cables
(a)
:
–
Two pins are connected to the ST3232 Receive/Transmit side.
–
Two pins are connected to the RS-232 Receive/Transmit connector side.
●
Connector J17 is a connector for standard IDC-to-DSUB converters.
●
Jumper J20 switches between RS-232 transmit signals or GPIO2:
–
If jumper is on pins 1 and 2, pin PL_GPIO2 is connected to U12 (ST3232) and the
COM0 is available on J17.
–
If jumper is on pins 2 and 3, pin PL_GPIO2 is connected to the expansion
connector J12 pin 9. In this case
the COM0 is available on CN13.
●
Jumper J21 switches between RS-232 receive signals or GPIO3:
–
If jumper is on pins 1 and 2, pin PL_GPIO3 is connected to U12 (ST3232) and the
COM0 is available on J17.
–
If jumper is on pins 2 and 3, pin PL_GPIO3 is connected to the expansion
connector J12 pin 11. In this case the COM0 is available on CN13.
a.
With 2 jumpers (inserted) it is possible to switch between two jumper inserted vertically and two jumpers
inserted horizontally. This enables the serial cable (null modem cable) to be adapted to the CPU board.
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