SI5338 SILABS [Silicon Laboratories], SI5338 Datasheet - Page 20

• Manufacturer Part Number: SI5338
• Description: I2C-PROGRAMMABLE ANY-FREQUENCY, ANY-OUTPUT QUAD CLOCK GENERATOR
• Manufacturer: SILABS [Silicon Laboratories]

Si5338
3.5.1. Ordering a Custom NVM Configuration
The Si5338 is orderable with a factory-programmed
custom NVM configuration. This is the simplest way of
using the Si5338 since it generates the desired output
frequencies at power-up or after a power-on reset
(POR). This default configuration can be reconfigured in
RAM through the I
“3.5.2. Creating a New Configuration for RAM”).
The first step in ordering a custom device is generating
an NVM file which defines the input and output clock
frequencies and signal formats. This is easily done
using the ClockBuilder Desktop software (see "3.1.1.
ClockBuilder™ Desktop Software" on page 16). This
GUI based software generates an NVM file, which is
used by the factory to manufacture custom parts. Each
custom part is marked with a unique part number
identifying the specific configuration (e.g., Si5338C-
A00100-GM). Consult your local sales representative
for more details on ordering a custom Si5338.
3.5.2. Creating a New Configuration for RAM
Any Si5338 device can be configured by writing to
registers in RAM through the I
factory programmed device must be configured in this
manner.
20
2
C interface after power-up (see
2
C interface. A non-
Rev. 0.6
When writing a configuration to RAM, use the following
procedure:
1. Create a device configuration (register map) using
2. Save the configuration using the Options > Save
3.5.3. Writing a Custom Configuration to RAM
Writing a new configuration (register map) to the RAM
consists of pausing the LOL state-machine, writing new
values to the IC accounting for the write-allowed mask
given in "6.1. Register Write-Allowed Mask" on page 28,
validating the input clock or crystal, locking the PLL to
the input with the new configuration, restarting the LOL
state-machine, and calibrating the VCO for robust
operation across temperature. The flow chart in
Figure 9 on page 21 enumerates the details:
Note: The write-allowed mask specifies which bits must be
ClockBuilder Desktop (v2.7 or later; see "3.1.1.
ClockBuilder™ Desktop Software" on page 16) or
manually using the equations in “AN411: Configuring
the Si5338”.
Register Map File or Options > Save C code Header
File, or create the register contents by the
conversions listed in AN411.
a. Configure the frequency plan.
b. Configure the output driver format and supply
c. Configure frequency and/or phase inc/dec (if
d. Configure spread spectrum (if desired).
e. Configure for zero-delay mode (if desired,
f.
read and modified before writing the entire register
byte (a.k.a. read-modify-write). “AN428: Jump Start: In-
System, Flash-Based Programming for Silicon Labs’
Timing Products” illustrates the procedure defined in
Section 3.5.2 with ANSI C code.
voltage.
desired).
see "3.9.5. Zero-Delay Mode" on page 24).
If needed go to the Advanced tab and make
additional configurations.