Atmel AT91EB55, Руководство пользователя

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Appendix A – Configuration Straps
5-4 AT91EB55 Evaluation Board User Guide
1709C–ATARM–28-Apr-05
Note: 1. Hardwired default position: To cancel this default configuration, cut (or place) the wire
(a jumper) on the board.
5.2 Power
Consumption
Measurement
Straps (JP5, JP9)
The JP5 strap enables the user to connect an ammeter to measure the AT91M55800A
global consumption (V
DDCORE
and V
DDIO
) when V
DDCORE
power supply is derived from
V
DDIO
(JP8 in 3V3 position). The user can measure the core consumption by connecting
another ammeter between JP8 1 – 2 or 2 – 3 depending on the power supply used to
power the core.
The JP9 strap enables the user to connect an ammeter to measure the AT91M55800A
APMC and RTC modules battery backup consumption (V
DDBU
).
5.3 Ground Links
(JP6)
The JP6 strap allows the user to connect the electrical and mechanical ground.
5.4 Increasing
Memory Size
The AT91EB55 evaluation board is supplied with two 128K bytes x 8 SRAM memories.
If, however, the user needs more than 256K bytes of memory, the devices can be
replaced with two 512K x 8, 3.3V, 10/15 ns SRAMs, giving in total 1024K bytes.
The AT91EB55 evaluation board is supplied with one 4-MB Serial Data Flash. If the
user needs more storage memory, 3 additional footprints are provided to fit AT45DB321
devices giving a total of 16M bytes.
JP3 RS-232 Driver Enabled
Open The RS-232 transceivers are enabled.
Closed The RS-232 transceivers are disabled. This authorizes users to connect the
corresponding PIO to their own resources via the I/O expansion connector.
JP7 Power Shut-down Feature
Open The power supply shut-down feature is disabled.
Closed The power supply shut-down feature is enabled. The user may shut-down the
board main power supply by using the APMC shut-down feature. The system
may be awakened by pushing the S1 Wake-Up push button or by programming
an alarm in the RTC module.
JP8 Core Power Supply Selection
2 – 3 The MCU core is powered by a 3.3V power supply.
1 – 2 Not supported on the current microcontroller revision.