UART Interface
1-24
ADSP-BF526 EZ-Board Evaluation System Manual
device mode, the USB 5V FET switch (
U23
) is turned
OFF
. When in host
mode, the ADSP-BF526 EZ-Board can supply 5V to a device, if desired.
A 5V, 500 mA current can be supplied only when the EZ-Board is
powered from the 5V wall source.
The 5V supplied to an external USB device is controlled by the
PG13
flag
pin of the processor.
PG13
must be connected on the board to signal
USB_VRSEL
through switch
SW20
. The
USB_VRSEL
signal controls an Analog
Devices ADM869L p-channel FET, which has an active low
ON
pin. By
default,
USB_VRSEL
is held high or a logic ‘
1
’ via a pull-up resistor and dis-
connects the 5V wall supply to
VBUS
. To set host mode and provide 5V to
a device, set
SW20
positions 2 and 5
OFF
and position 6
ON
. This disables
push button 2. Note that signal
HOSTADDR
is shared with push button 2; do
not use the push button when controlling the
USB_VRSEL
signal.
By default,
SW20
positions 2, 5, and 6 are
ON
,
OFF
, and
OFF
(respectively)
and shut off the p-channel FET (
U23
).
For more information, see “GPIO
Enable Switch (SW20)” on page 2-16.
The USB OTG interface has a mini-AB connector (
P8
); a cable that plugs
into
P8
is shipped with the EZ-Board.
Use the example programs in the EZ-Board installation directory to learn
about the ADSP-BF526 processor’s device and host modes. For more
information about the USB interface, refer to the
ADSP-BF52x Blackfin
Processor Hardware Reference
.
UART Interface
The ADSP-BF526 processor has two built-in universal asynchronous
receiver transmitters (UARTs).
UART0—1
share the processor pins with
other peripherals on the EZ-Board.
UART1
has full RS-232 functionality via the Analog Devices 3.3V
ADM1385 line driver and receiver (
U21
). The ADSP-BF526 processor is
Содержание ADSP-BF526 EZ-Board
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