Hardware Preparation and Installation
MC92602 Reduced Interface SerDes Design Verification Board User’s Guide, Rev. 3
Freescale Semiconductor
2-5
2.4.4
3.3V_CLK_OUT
n
SMA Connectors
Four single-ended, 3.3-V level, clock signals are available on SMA connectors to drive other instruments.
Between the MC100ES8111 output and the 4 SMAs, is an MPC9456 which performs a differential PECL
to single-ended +3.3-V LVTTL/CMOS level shift. These CMOS outputs are series terminated on the
board, then connect to the SMA connectors labeled 3.3V_CLK_OUT1, 3.3V_CLK_OUT2,
3.3V_CLK_OUT3, and 3.3V_CLK_OUT4. All of the outputs of the MPC9456 can be disabled by setting
the DIP switch SW1, switch 7 to the ‘off’ position.
2.4.5
Clock Frequency Selection
To accommodate the fact that the MC92602 can receive data on both edges of the reference clock (DDR),
of which many pieces of test equipment are single-edge triggered (SDR), the MC92602DVB clock outputs
can be programmed to be either the same as the supplied frequency or half the supplied frequency by
setting SW1, switches 3, 5, and 6 to either ‘on’ (divide-by-one) or to ‘off’ (divide-by-2). This allows the
interface between the board and the bench to be either single data rate (SDR) with a double speed clock,
or double data rate (DDR) with a single speed clock.
The 1.5V_CLK_OUT
n
SMA outputs will always follow the clock supplied to the MC92602 and the
frequency is programmed via SW1, switch 3. SMA outputs 3.3V_CLK_OUT1 and 3.3V_CLK_OUT2 can
be programmed by setting SW1, switch 5 and 3.3V_CLK_OUT3 and 3.3V_CLK_OUT4 can be
programmed by setting SW1, switch 6.
Table 2-2
lists the switch positions and output frequencies. The
input frequency, CLK_IN refers to either the onboard oscillator frequency or the externally applied clock
source frequency.
NOTE
Only those frequencies listed in the
MC92602 Quad 1.25 Gbaud Reduced
Interface SerDes Reference Guide
are considered valid. Freescale does not
guarantee operation of the MC92602 at frequencies other than those listed
in the reference Guide.
Table 2-2. SW1 Settings and Output Frequencies
SW1
Switch
Switch
Position
MC92602
REF_CLK_P,
REF_CLK_N,
and 1.5V_CLK_OUTn
3.3V_CLK_OUT1,
3.3V_CLK_OUT2
3.3V_CLK_OUT,
3.3V_CLK_OUT4
3
On
CLK_IN
N/A
N/A
Off
CLK_IN/2
N/A
N/A
5
On
N/A
CLK_IN
N/A
Off
N/A
CLK_IN/2
N/A
6
On
N/A
N/A
CLK_IN
Off
N/A
N/A
CLK_IN/2
Содержание MC92602
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