Information

35.3.2.1 SC[MODE_LV]=00
The internal bandgap is enabled to generate an accurate 1.2 V output that can be trimmed
with the TRM register's TRIM[5:0] bitfield. The bandgap requires some time for startup
and stabilization. SC[VREFST] can be monitored to determine if the stabilization and
startup is complete.
The output buffer is disabled in this mode, and there is no buffered voltage output. The
Voltage Reference is in standby mode. If this mode is first selected and the tight
regulation buffer mode is subsequently enabled, there will be a delay before the buffer
output is settled at the final value. This is the buffer start up delay (Tstup) and the value is
specified in the appropriate device data sheet.
35.3.2.2 SC[MODE_LV] = 01
Reserved
35.3.2.3 SC[MODE_LV] = 10
The tight regulation buffer is enabled to generate a buffered 1.2 V voltage to
VREF_OUT. If this mode is entered from the standby mode (SC[MODE_LV] = 00,
SC[VREFEN] = 1) there will be a delay before the buffer output is settled at the final
value. This is the buffer start up delay (Tstup) and the value is specified in the
appropriate device data sheet. If this mode is entered when the VREF module is enabled
then you must wait the longer of Tstup or until SC[VREFST] = 1.
35.3.2.4 SC[MODE_LV] = 11
Reserved
35.4 Initialization/Application Information
The Voltage Reference requires some time for startup and stabilization. After
SC[VREFEN] = 1, SC[VREFST] can be monitored to determine if the stabilization and
startup of the VREF bandgap is complete.
Chapter 35 Voltage Reference (VREFV1)
K10 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc. 853