Leds; Eeprom; Usb Power Switch; I 2 C Source Jumpers - Analog Devices SSM2380 User Manual

UG-248

LEDS

The LEDs provide feedback to the user about the status of the
Cypress USB microcontroller. The function of each LED is
shown in Table 1.
Table 1. LED Functions
Reference
Designator Color Function
D1 Red 5 V power is supplied over the USB bus
D2 Yellow I 2 C mode is active
D3 Blue GPIO LED, for firmware debug purposes
D4 Yellow SPI mode is active
D5 Blue USB power switch enabled (USB_PWR_ON)

EEPROM

The USBi has an EEPROM on the I
it uses to indicate its vendor ID and product ID to the PC, as
well as boot its internal program. The EEPROM is an important
system element that identifies the board to the host PC and
stores the firmware for the Cypress USB interface. The EEPROM
is programmed during manufacturing via the H1 connector.
Avoid having any other EEPROMs in your system design at
this address. This EEPROM is not write-protected; therefore,
an attempt to write to Address 0x51 overwrites the USBi's
on-board EEPROM, and the USBi will cease to function. The
USBi cannot be reprogrammed without returning it to Analog
Devices.

USB POWER SWITCH

The SSM2380 evaluation board is capable of taking 5 V power
from the USB port after the Cypress USB microcontroller has
finished its boot up process. The USB_PWR_ON signal, which
can be set in the SSM2380 software, appears on one pin of the
Cypress microcontroller. This signal controls, Q1 and Q2, create
a connection between USB power and the supply rail. D5, a blue
LED, lights up when this supply is activated. Note that the
current available from the USB bus is limited; therefore, the
amplifier power stage may not drive low impedance loads
properly.
2 C bus at Address 0x51, which
Rev. 0 | Page 4 of 20
Evaluation Board User Guide
I 2 C SOURCE JUMPERS
If an external I 2 C source is to be used, place the JP1, JP2, and
JP3 jumpers such that they connect the device I
external I 2 C lines. Otherwise, they should connect the device
I C lines to the on-board I C lines, as shown in the red
2 2
rectangular area of Figure 4. If an external I
external I 2 C source can be attached to H2, following the
silkscreen labels displayed on the board.
The voltage of the external I 2
value set on JP4; the two voltages are taken from two separate
on-board regulators. The on-board I
in either configuration.
For the Cypress USB microcontroller to boot properly from the
EEPROM, it may be necessary to power down (or disconnect)
any other devices from the I
2
In this case, remove the external 5 V supply while the USB
connection is first established, or remove the JP2 and JP3
jumpers and replace them only after the connection is activated.
Figure 4. Jumpers as Configured for On-Board I
2 C lines to the
2 C is used, an
C interface should match the
2 C interface works properly
C bus, including the SSM2380.
2
C Operation