Dacu for the Diva SOM

Info Box Applies to Dacu Applies to Diva

Introduction

When used in combinaton with Diva SOM, DACU requires the use of DivaEVB-Lite acting as adaptation board. The overall system looks like the following picture and it is composed by

• Diva SOM
• DivaEVB-Lite
• Dacu carrier board.

In order to make DACU compatible with this configuration, some additional wired connections are required, as detailed in the schematics. The following sections explains in more detail these issues.

Block diagram

The following figure shows the system block diagram:

Power supply

This is the power-up sequence of the whole system (it matches Diva recommended power-up sequence):

1. power supply or wall adapter connected to DACU's JP2 is turned on
2. DACU's U15 DC/DC PSU is turned on; since the output of this DC/DC is connected to DivaEVB-Lite's VREG rail, Diva SOM is powered
3. Diva performs its own power-on sequence
4. DivaEVB-Lite's U4 linear regulator is enabled by Diva
5. DivaEVB-Lite's 3.3V rail raises; since this rail is connected to DACU's ENA_3.3V, DACU's U16 DC/DC PSU is enabled and DACU's circuitry interfacing processor's I/O is powered

DACU's USB host port

DACU's USB host port power is controlled by Micrel MIC2026 Dual-Channel Power Distribution Switch (U7). B channel of this swith is associated to USB host port. In order to control this channel, Diva's USB1_DRVVBUS and VUSB_VBUS1 signals are connected to ENB and FLGB pads respectively.

Schematics

Please note that Orcad CIS is required to get all the information about BOM variants included in .dsn files. PDF files show the view of the default BOM variant used to manufacture the board. Components that are not populated are denoted as "Do Not Stuff".

• Orcad: http://mirror.dave.eu/diva/dacu//dacu-DACUEVB_2.0.2-dsn.zip
• PDF: http://mirror.dave.eu/diva/dacu//dacu_S.DACUD000I2R.2.0.2.pdf

BOM

• http://mirror.dave.eu/diva/dacu/dacu_BOM_S.DACUD000I2R.2.0.2.csv_.zip