Atmel ATEVK525 Guia do Utilizador descarregar pdf (Página 12)

Using the ATEVK525

2-12 ATEVK525 Mass Storage Board for AVR

7740B–AVR–03/08

2.4 LEDs

Three LEDs are on the board:

– PWR_FAIL: orange LED that signals an overvoltage condition if the protection

circuit is mounted. This LED is optional.

– WRITE: red LED connected to PORTD7 of micro (also LED1 on STK525), that

may be driven by software when initiating a SCSI Write command

– READ: green LED connected to PORTD5 of micro (also LED3 on STK525),

that may be driven by software when initiating a SCSI Read command

Figure 2-7 . On-board SCSI signalling LEDs

2.5 Test Points

Several test points are included on the board to facilitate debug during development. All

the test points are circular pads with a silk-screen printing that indicates the

corresponding signal:

– VCC: power supply voltage (should be 3.3V), taken after the power protection

circuit

– GND: power supply ground

– SD_MISO: SD/MMC card MISO signal (card output)

– SD_MOSI: SD/MMC card MOSI signal (card input)

– SD_SCK: SD/MMC clock signal

– SD_CS: SD/MMC chip select signal (active low)

– NF_CLE: NAND Flash CLE signal

– NF_ALE: NAND Flash ALE signal

– NF_RE: NAND Flash RE# signal

– NF_WE: NAND Flash WE# signal

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