AT91EB55 datasheet(11/37 Pages) ATMEL

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AT91EB55 Evaluation Board User Guide

4-1

Section 4

Circuit Description

4.1

AT91M55800A

Processor

Figure 1 in “Appendix B – Schematics” shows the AT91M55800A. The footprint is for a

176-pin TQFP package.

Strap CB15 enables the user to choose between the standard ICE debug mode and the

JTAG boundary scan mode of operation.

The operating mode is defined by the state of the JTAGSEL input detected at reset.

Jumper JP5 can be removed by the user to allow measurement of the current demand

by the whole microcontroller (V

DDIO and VDDCORE). Jumper JP8 can be removed to mea-

sure the core microcontroller consumption (V

DDCORE). See Figure 8 in “Appendix B –

Schematics.”

Jumper JP9 can be removed by the user to allow measurement of the current demand

by the APMC and RTC microcontroller modules (V

DDBU). See Figure 8 in “Appendix B –

Schematics.”

4.2

Expansion

Connectors and

JTAG Interface

The two expansion connectors (I/O expansion connector and EBI expansion connector)

and the JTAG Interface are described below.

The I/O and EBI expansion connectors pin-outs and positions are compatible with the

other evaluation boards (except for the I/O expansion connector pin-out and position of

the EB40) so that users can connect their prototype daughter boards to any of these

evaluation boards. For the I/O expansion connector, rows A and B are position and

pinout compatible.

4.2.1

I/O Expansion

Connector

The I/O expansion connector makes the general purpose I/O (GPIO) lines, VCC3V3 and

Ground available to the user. Configuration straps CB2, CB3, CB4, CB5, CB6, CB13,

CB14 and CB17 are used to select between the I/O lines being used by the evaluation

board or by the user via the I/O expansion connector. The connector is not fitted at the

factory; however, the user can fit any 32 x 3 connector on a 0.1" (2.54 mm) pitch.

4.2.2

EBI Expansion

Connector

The schematic illustrated in Figure 4 in "Appendix B - Schematics" also shows the Bus

expansion connector, which, like the I/O expansion connector, is not fitted at the factory.

The user can fit any 32 x 2 connector on a 0.1" (2.54 mm) pitch to gain access to the

data, address, chip select, read/write, oscillator output and wait request pins. VCC3V3

and Ground are also available on this connector. Configuration strap CB1, when open,

allows the user to connect the EBI expansion connector to the MPI expansion connector

of an AT91EB63 evaluation board without fearing any conflict problem.

4.2.3

JTAG Interface

An ARM-standard 20-pin box header (P5) is provided to enable connection of an ICE to

the JTAG inputs on the AT91. This allows code to be developed on the board without

using system resources such as memory and serial ports.

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