CPU board hardware description
UM0842
30/50
Doc ID 16542 Rev 4
The debug feature can be selected by setting Switch SW1 bits [2:1].
Please refer to the documentation of the trace box manufacturer for more information on the
ETM interface (www.lauterbach.com, www.agilent.com, www.yokogawa.com).
A.2.5 Serial
interface
One serial interface port is available. Typically used as an OS monitor, this port is available
on the J17 connector. It is possible to simulate a cross cable by changing the position of the
J22 jumpers.
Figure 26.
Serial cable setting
A.2.6 Real
time
clock (battery powered)
The real time clock (RTC) is powered by an external battery (3 V) in order to prevent data
loss even if the main power supply is switched off.
A.2.7
General power supply
From a 5 V external AC/DC regulator power source, this block generates all the required
voltages as follows:
●
1.2 V (Switching regulator PM6641) to supply the internal logic of the SPEAr320 MPU
●
1.8 V (Switching regulator PM6641) for the DDR2 memory
●
2.5 V (LDO regulator) for the analog portion of SPEAr320
●
3.3 V (Switching regulator PM6641) to supply the other interfaces
A power monitor is also present to provide the general reset of the board.
Table 29.
Switch SW1 bits [2:1]
Bit 2
Bit 1
Description
0
0
No debug features available
0
1
The ARM JTAG is connected to J4
Nul
Modem
Cable
J22
2
4
1
3
Cross
Cable
J22
2
4
1
3
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