■ Data 1 (32 bits) = 0x0201.0100
■ Data 2 (32 bits) = 0x0D08.0503
■ Data 3 (32 bits) = 0x5937.2215
If the data bytes are correct, then the device is returned to factory condition. During the
return-to-factory settings function, the following events occur:
■ The RAM is erased in the Hibernation module
■ The system SRAM is erased
■ The
FMPPEn
registers are set to 0xFFFF.FFFF (to allow a Flash erase operation to occur)
■ The EEPROM pages are erased
■ A mass-erase of the flash array occurs
■ The
BOOTCFG
register is written with 0xFFFF.FFFE
Once the return-to-factory settings sequence is completed, the
CDOFF
field of the
HSSR
register is
written with 0x00.0000, indicating a successful completion and activating a system reset.
5.3
Initialization and Configuration
The PLL is configured using direct register writes to the
PLLFREQn
,
MEMTIM0
, and
PLLSTAT
registers. The steps for initializing the system clock from POR to use the PLL from the main oscillator
is as follows:
1.
Once POR has completed, the PIOSC is acting as the system clock.
2.
Power up the MOSC by clearing the
NOXTAL
bit in the
MOSCCTL
register.
3.
If single-ended MOSC mode is required, the MOSC is ready to use. If crystal mode is required,
clear the
PWRDN
bit and wait for the
MOSCPUPRIS
bit to be set in the
Raw Interrupt Status
(RIS)
, indicating MOSC crystal mode is ready.
4.
Set the
OSCSRC
field to 0x3 in the
RSCLKCFG
register at offset 0x0B0.
5.
If the application also requires the MOSC to be the deep-sleep clock source, then program the
DSOSCSRC
field in the
DSCLKCFG
register to 0x3.
6.
Write the
PLLFREQ0
and
PLLFREQ1
registers with the values of
Q
,
N
,
MINT
, and
MFRAC
to
the configure the desired VCO frequency setting.
7.
Write the
MEMTIM0
register to correspond to the new system clock setting.
8.
Wait for the
PLLSTAT
register to indicate the PLL has reached lock at the new operating point
(or that a timeout period has passed and lock has failed, in which case an error condition exists
and this sequence is abandoned and error processing is initiated).
9.
Write the
RSCLKCFG
register's
PSYSDIV
value, set the
USEPLL
bit to enabled, and
MEMTIMU
bit.
June 18, 2014
246
Texas Instruments-Production Data
System Control