Atmel AT91EB42 Section Circuit Description, Processor, Expansion, Connectors, Jtag Interface

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Section 4

Circuit Description

4.1AT91M42800 Figure 6-1 on page 6-2shows the AT91M42800. The footprint is for a 144-pin TQFP

 

Processor

package.

 

 

Strap CB20 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 (see Figure 6-8 on page 6-9in Section 6, “Appendix B – Schematics”) can

 

 

be removed by the user to allow measurement of the current demand by the whole

 

 

microcontroller (VDDIO and VDDCORE). Jumper JP8 can be removed to measure the core

 

 

microcontroller consumption (VDDCORE).

 

 

 

4.2

Expansion

The two expansion connectors, I/O expansion connector and EBI expansion connector,

 

Connectors and

and the JTAG interface are described below.

 

JTAG Interface

The I/O and EBI expansion connectors’ pinout and position are compatible with the

 

 

other evaluation boards (except the I/O expansion connector pinout and position of the

 

 

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

 

 

ation boards.

4.2.1

I/O Expansion

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

 

Connector

and Ground, available to the user. Configuration straps CB2, CB3, CB4, CB11, CB13,

 

 

CB14, CB15, CB17, CB18 and CB19 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 con-

 

 

nector is not fitted at the factory; however, the user can fit any 32 x 2 connector on a 0.1"

 

 

(2.54 mm) pitch.

4.2.2

EBI Expansion

The schematic (Figure 6-4 on page 6-5in Section 6, “Appendix B – Schematics”) also

 

Connector

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 con- nector to the MPI expansion connector of an AT91EB63 evaluation board without any conflicts.

4.2.3JTAG Interface An ARM®-standard 20-pin box header (P5) is provided to enable connection of an ICE interface 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.

AT91EB42 Evaluation Board User Guide

4-1

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Contents AT91EB42 Evaluation Board User Guide Page Table of Contents Table of Contents Appendix a Configuration StrapsEvaluation Board Two serial ports Section OverviewScope DeliverablesASB OverviewLayout Section Setting Up the AT91EB42 Evaluation BoardElectrostatic Warning Current TestingBoard MeasuringProgram Section On-board SoftwareAT91EB42 Evaluation Board On-board Software Programmed Default Memory MappingDefault Speed DownloaderExpansion ConnectorsSection Circuit Description ProcessorCrystal Quartz PowerMemories ConverterCircuit Description Circuit Description Configuration Straps CB1 23, JP1 Section Appendix a Configuration StrapsAppendix a Configuration Straps CB17 SPI Eeprom Enabling CB18 PB20 ADC Write Access SignalCB19 PB18 End of Fast Charge Signal CB15 Serial DataFlash EnablingJP6 Increasing Memory Size ConsumptionMeasurement Strap JP5Schematics Section Appendix B SchematicsPCB Layout Appendix B SchematicsEBI Memories AT91EB42 Evaluation Board User GuideAppendix EBI Memories SchematicsI/O and EBI Expansion Connectors Valbp Serial InterfaceAT91M42800 ICE Reset and Jtag Schematics InterfaceVDDCORE=1.8V Saft VRE 1/2 AA AT91EB42 Evaluation Board User Atmel Headquarters Atmel Operations
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