17
ispClock5400D Evaluation Board
Lattice Semiconductor
User’s Guide
- Ref Select, reference A or B MUX control
- Phase–Skew value, 16 values
- Output Delay Mode for Zero-Delay mode or FOB, Fan-Out Buffer mode
4.
Double-click the Bank 2 output block
(0x0, 8 TUD, 0=Disable)
of the schematic.
The Output Group-1 Bank 2 Time Skew dialog appears.
5.
Specify
3
and click
OK
.
The output block display is updated to 0xB, 3 TUD, 0=Disable to indicate the new configuration of the block.
6.
From the ispClock5406D Output Group 1 Control dialog click the
Write
button.
The I
2
C utility writes the control registers to the ispClock5406D I
2
C interface and updates the time skew by
three steps (18 ps x 3 = 54 ps).
7.
Note the updated scope display.
The BANK0_P and BANK2_P outputs will be de-skewed in the same manner as the reprogrammed device
demonstrated in section 6.1.2 Modify Clock Time Skew of the user’s guide. The value is written to the register
and active at this point unless an I
2
C soft or full reset or hardware power on reset occurs.
For more information on I
2
C control registers, see the
ispClock5400D Family Data Sheet
.
8.
From the ispClock5406D Output Group 1 Control dialog click the
OK
button.
You may wish to experiment with the I
2
C utility interface to apply the same clock inversion and phase skew
changes as documented in the Invert Clock Output and 6.1.4 Modify Clock Phase Skew section of this docu-
ment.
To reset the ispClock5406D device via the I
2
C interface:
1.
From the ispClock5406D I
2
C Utility, click the
Soft Reset
button.
The ispClock5406D Soft Reset dialog prompt appears and the I
2
C utility issues the I
2
C command to assert soft
reset. During this state the PLL, Dividers, Phase and Time Skew blocks are reset. The differential outputs of
the ispClock5406D banks disabled during the soft reset state.
Figure 19. ispClock5406D Soft Reset Dialog - Soft Reset State
2.
Click
OK
.
3.
Click the
Soft Reset
button.
The ispClock5406D Soft Reset dialog prompt appears and the I
2
C utility issues the I
2
C command to release
soft reset.
