Owner's manual

CDB61884
DS485DB1 5
2. BOARD COMPONENT DESCRIPTIONS
2.1 Power Connections
Power for the evaluation board is supplied by an
external +3.3 V DC power supply. A +5 V DC
power supply can also be connected to the on-board
control logic. The LED labeled “D3” will illumi-
nate when power is supplied to the on-board con-
trol logic.
– Connect the +3.3 VDC power supply to the +3V
binding post and the +5 VDC power supply to
the +5 V binding post if 5 Volt logic is required
– Jumper J13 shown in Figure 2 allows all the
external logic on the evaluation board to be
connected to either +3 V or +5 V binding post.
– To measure the current consumption of only
the CS61884 device, place a short block on
Jumper J13 to connect the Vlogic power
supplies to the +5 V binding post. This will
isolate the CS61884 device from all the on-
board logic, to allow the current measurement
to be made at the +3 V binding post.
2.2 Master Clock Selection
In both hardware and host modes, the MCLK pin is
configured by placing a short block on one of the
positions of bed stake header J1. Figure 3 shows
the different positions of the J1 bed stake header.
– A 2.048 MHz clock oscillator is provided on the
evaluation board for use as the on-board clock
source for all E1 modes.
– A 1.544 MHz clock oscillator is also provided
with the evaluation board for use as the on-
board clock source for the T1/J1 operation
modes.
– A BNC connector (labeled J16) provides the
connection for an external clock source.
J13
3V
5V
On-board logic connected
to +3 V binding post
On-board logic connected
to +5 V binding post
VLOGIC
J13
3V
5V
VLOGIC
Figure 2. On-board Logic Power Selection
MCLK
J1
Data Recovery Mode
EXTERNAL SOURCE
HIGH
OSCILLATOR GND
MCLK
J1
External Clock Source
HIGH OSCILLATOR GND
J1
Receivers Powered Down
HIGH
OSCILLATOR GND
J1
HIGH OSCILLATOR GND
On-board Oscillator
MCLK
MCLK
EXTERNAL SOURCEEXTERNAL SOURCE
EXTERNAL SOURCE
Figure 3. Master Clock Selections