UM0804

Block descriptions

Doc ID 16303 Rev 2

11/25

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).

6.6

Serial interface

One serial interface port is available. This typically used as OS monitor, is available on the

J10 connector. It is possible to simulate a cross cable by changing the position of the J5

jumpers.

Figure 4.

Serial cable setting

6.7

A/D interface

Eight analog input lines are provided on the J3 connector. The connector also allows you to

determine the conversion range by setting the conversion limits on pins J3-19 (lower limit)

and J3-1 (upper limit). The default setting is to have pins 1-2 and 19-20 shorted by jumpers.

In this way the conversion range is set to the maximum value (0 ~ 2.5V with a granularity of

2.44 mV) but by removing the two jumpers and providing different values on pin 1 and 19 it

is possible to reduce the range and thus increase the granularity. For example if you input 1

V on J3-19 and 2 V on J3-1 the range will be 1 V ~ 2 V in steps of less than 1 mV.

In any case the following relationships between the pins should be ensured:

6.8

Real time clock (battery powered)

The real time clock (RTC) is powered with an external battery (3 V) in order to avoid losing

its data even if the main power supply is switched off.

Table 1.

Switch 2 bits [2:1]

Sw2

Description

21

0

0

No debug features available

0

1

The ARM JTAG is connected to J4

1

0

The ARM ETM bus available on J13 and J14

Null

modem

Cable

JP5

24

13

Cross

Cable

JP5

24

13

0 V

≤

J3-19

≤

J3 17 ~ 3

≤

J3-1

≤

2.5 V

AGND

≤

Vref_n

≤

ADC_In

channels

≤

Vref_p

≤

AVDD