UM0842 datasheet(30/50 Pages) STMICROELECTRONICS

30 / 50 page

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

No debug features available

The ARM JTAG is connected to J4

Nul

Modem

Cable

J22

Cross

Cable

J22

UM0842 Datasheet(PDF) 30 Page - STMicroelectronics