Trion 8 BGA81 Development Kit User Guide
Figure 2: Trion
™
8 BGA81 Development Board Components
Trion T8F81C
Device
SPI NOR Flash
Atmel
Microcontroller
On-Board
Low Dropout
Regulators
Oscillator Clock
33.333 MHz
Bank 1A/1B
GPIO (J3)
Select PLL Input
Source (J27)
Mini-USB
Type B
Voltage Select
for Bank 2B
VDDIO (J8)
Voltage Select
for Bank 2A
VDDIO (J6)
Bank 2A
GPIO (J4)
Bank 2B
GPIO (J5)
User LEDs
User Pushbuttons
Power
OK LED
CDONE
LED
Reset Pushbutton
5 V Power for
External Devices
The Atmel microcontroller has a built-in USB controller; it receives the T8
configuration bitstream from a USB host and writes to the on-board SPI NOR
flash memory. The microcontroller can also write the configuration bitstream
directly to the device when it is configured to boot in passive mode.
The SPI NOR flash memory stores the configuration bitstream it receives from
the microcontroller. The T8 device accesses this configuration bitstream when it is
in active configuration mode (default).
The board's main power supply is the 5 V DC (500 mA) it receives from the USB
interface. The board regulates down the 5 V DC using on-board low dropout
regulators to provide the necessary voltages for the T8 device, SPI flash memory,
and on-board oscillator.
Power On
Upon power-up, the USB power supply is input to the on-board regulators to
generate the required 3.3 V, 2.5 V, 1.8 V, and 1.1 V for components on the board.
When these voltages are up and stable, the board asserts a “power good” signal
(pulled high) from the components' respective regulators. This power good signal
triggers the Atmel microcontroller to bring the T8F81C device out of reset.
The power good signal is also connected to a green LED (D1). By default, the
power good signal is pulled low, and the LED is turned off. When the board
asserts the power good signal, the LED turns on, giving you a visual confirmation
that the power supplies on the board are up and stable.
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