MC9S12KG128 Datasheet, PDF (441/600 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 14 Dual Output Voltage Regulator (VREG3V3V2)
14.3.2 Register Descriptions
The following paragraphs describe, in address order, all the VREG3V3 registers and their individual bits.
14.3.2.1 VREG3V3 — Control Register (VREGCTRL)
The VREGCTRL register allows to separately enable features of VREG3V3.
R
W
Reset
Field
2
LVDS
1
LVIE
0
LVIF
7
6
5
4
3
2
1
0
0
0
0
0
0
LVDS
LVIE
LVIF
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 14-2. VREG3V3 — Control Register (VREGCTRL)
Table 14-3. MCCTL1 Field Descriptions
Description
Low-Voltage Detect Status Bit — This read-only status bit reflects the input voltage. Writes have no effect.
0 Input voltage V_DDA is above level V_LVID or RPM or shutdown mode.
1 Input voltage V_DDA is below level V_LVIA and FPM.
Low-Voltage Interrupt Enable Bit
0 Interrupt request is disabled.
1 Interrupt will be requested whenever LVIF is set.
Low-Voltage Interrupt Flag — LVIF is set to 1 when LVDS status bit changes. This flag can only be cleared by
writing a 1. Writing a 0 has no effect. If enabled (LVIE = 1), LVIF causes an interrupt request.
0 No change in LVDS bit.
1 LVDS bit has changed.
NOTE
On entering the Reduced Power Mode the LVIF is not cleared by the
VREG3V3.
14.4 Functional Description
Block VREG3V3 is a voltage regulator as depicted in Figure 14-1. The regulator functional elements are
the regulator core (REG), a low-voltage detect module (LVD), a power-on reset module (POR) and a
low-voltage reset module (LVR). There is also the regulator control block (CTRL) which represents the
interface to the digital core logic but also manages the operating modes of VREG3V3.
14.4.1 REG — Regulator Core
VREG3V3, respectively its regulator core has two parallel, independent regulation loops (REG1 and
REG2) that differ only in the amount of current that can be sourced to the connected loads. Therefore, only
REG1 providing the supply at V_DD/V_SS is explained. The principle is also valid for REG2.
MC9S12KG128 Data Sheet, Rev. 1.15
Freescale Semiconductor
441