1. MSP432™ MCUs Training Part 3: Power System
Welcome to part three of the MSP432 MCU training series. In this section we will talk about the power system of the MSP432P4XX

2. Power | Feature Overview
Wide supply range with true 1.8V+/-10% operation: 1.62V-3.7V
Two internal core voltages for system frequency power-scaling
1.2V: 1-24MHz operation
1.4V: 1-48MHz operation
Two internal voltage regulators to adapt for power requirements/profiles
LDO: default regulator
DC/DC: additional regulator for better higher frequency
Supply Voltage Monitor & Supervisor
Low performance modes for extremely low power in LPM3/4/x.5
DriverLib-assisted power state transitions & configurations
From a feature overview the power system provides a wider range of power supply with two 1.8V operations so you could use the device all the way from 1.62V to 3.7V. There are two internal core voltages to enable the system through conceived power scaling. For example if you need to run your system from 1-24MHz you could use 1.2V code/ When you need to boost your power from 1-48Mhz you could use the 1.4V. To generate the internal core voltage, an internal voltage regulator could be used. Similar to many MSP430 devices we provide an ultra-low power regular. That is a regulator that could be used to regulate the voltage. Howe r, in addition to the LDO we will also provide a DC to DC regulator. This additional regulator is very efficient at high frequency and high load conditions. The supply voltage monitor and supervised module has also been simplified significantly compared to the MSP430 family. It also adds low power performance modes for extremely low power consumption in LPM3, LMP4 and the** 5mode. The last thing to note, this might be the most important feature, is that all the power transitions, configurations and operations can be done using the driver library API

3. Power | Operating Conditions
VMIN for LDO
BOR, reset released
VMIN for both Flash accesses & SVSMH
VMIN for DC/DC
VCC
1.62V
1.65V
1.71V 2V
3.7V
As previously mentioned, the MSP432 has a wide operating range all the way from 1.62Vall the way to 3.7V. The startup voltage requirement though is 1.65V and at 1.71V both flash accesses and supply voltage monitor can be enabled. The DC/DC regulator does require minimum voltage of 2V for operation. The LDO could actually start operating all the way down to 1.62V
Operating Voltage Range
Either Flash or SVSMH (not both) can be enabled

4. Power | Regulators: LDO & DC-DC
LPM3
AM_LF
128kHz
1MHz
high MHz
48MHz
LPM0 & Active Modes
32-50kHz
LDO
LDO
DC-DC
Default regulator at startup
Secondary, requires external inductor
VCC = [1.62V-3.7V]
VCC = [2.0V-3.7V]
Available in all power modes
Available in LPM0 & Active Modes
Flexible with scalable output loads for low power modes
Efficient, optimized for high-speed/high-load operations
Fast on/off switching operations
Slow on/off/failsafe switching from/to LDO
There are two internal voltage regulators, the LDO and the DCDC. By default the LDO is the always the chosen regulator at startup. It is the most versatile one because it can operate all the way from 1.62V to 3.7V. The LDO could be used in all power low power modes or active power modes. It is also very flexible and scalable to generate different output loads depending on the low power mode that is being used. The LDO also supports fast on and off switching operation, this could become quite handy when your application needs to switch in and out of active and low power modes frequently. On the other hand the DCDC is secondary regulator also requires an inductor so there is an additional cost that needs to be considered in the system. It has a smaller operating range starting at 2V all the way to 3.7V. The DCDC is also only available in LPM0 as well as Active modes. So what lacks in terms of operating range, it makes up in its efficiency and it is highly optimized for high speed and high load operations. DCDC also requires a longer time to turn on and turn off from the LDO. In the event that Vcc drops below 2V the DCDC will automatically turn on the fail safe switching mode and turn back to LDO. Once the Vcc rises above 2.0v again it will switch back to DCDC automatically.

5. MSP430 & 432 Low-Power Modes MSP430 MSP432 Industry/ARM description
Comments
Active
Active Mode
CPU & peripherals
Low-Frequency Active
Low-Power Run
CPU & peri. <128kHz
LPM0
Sleep
Peri. on, CPU off
Low-Frequency LPM0
Sleep + CLK < 128kHz
LPM1
N/A
LPM2
LPM3
Deepsleep (ARM) Stand-by w/ RAM & RTC
A/BCLK, <32kHz, some peripherals available
LPM4
Stand-by with RAM
No clocks, some peripherals available
LPM3.5
Shutdown
RTC w/o RAM
LPM4.5
** Not in video

6. Power | MSP432 Flexible Operating Modes
ACTIVE
Low-Frequency (Active/LPM0)
LPM0
LPM3 LPM4
LPM3.5
LPM4.5
Current
100uA/MHz (DCDC) 166uA/MHz (LDO)
70uA
65uA/MHz (DCDC)
100uA/MHz (LDO)
<900nA
<670nA
<100nA
CPU
Retention
FLASH
SRAM
LDO
In LDO mode
Low Drive Mode
DC-DC
In DCDC mode
PSS Bandgap
Sampled Mode
Clocks
Only BCLK
Core Domain Logic
Backup Domain Logic (RTC/WDT)
Active
I/O State
LPMx.5 modes
Ultra low leakage modes, with no state retention (as low as 670nA typ with RTC active)
LPM3.5: allows wake up from RTC & WDT events
LPM4.5: allow reset wake up through reset
Active modes at Core Voltage 0
Low power, medium performance mode : 0 – 24MHz
Can be used with regulation either through LDO (for maximum efficiency) or DCDC
Active modes at Core Voltage 1
High performance, high efficiency mode : 0 – 48MHz
Can be used with regulation either through LDO or DCDC (for maximum efficiency)
Low-Frequency modes
Special low power low frequency option available for both active and LPM0 modes Total device current consumption below 80uA
CPU execution at 128KHz max, Flash, SRAM and peripherals remain active at the lower speeds
LPM0
CPU off, all peripherals & clocks active
LPM3 & LPM4
Ultra low leakage modes with full state retention (as low as 900nA typ with RTC active)
Let’s take a quick look at the MSP432 flexible operating power modes. MSP432 Family introduces the similar power modes that you might have seen on the MSP430 including active, LPM0 LPM0 LPM3.5 and LMP4.5. However, two new modes have been introduced. First off, let’s start with active mode. In active mode you could either use Vcore voltage or low power and medium performance when the system needs to run anywhere between 0-24MHz you could use Vcore level 0. At this point either regulator can be used, LDO or DC-DC. For high performance at higher frequencies such as from 24-48MHz it is highly recommended that you use a DC-DC at this point. When you use an LDO the current consumption is around 166uAh and the current consumption in active mode is around 100mAh. Two new modes have been introduced to the MSP432 and those are the low frequency mode. The low frequency mode is the special mode that keeps everything in the system active, this could include the CPU. However all clocks must be less or equal than 120KHz. This allows for the entire system to consume 70uAh or less. The LPM0 mode is very similar to the MSP430; in this mode all peripherals and clocks are active except the CPU and main clock. In this mode the current consumption is anywhere from uA/MHz depending on the regulator that you use. Next LPM3 and LPM4 are also low power modes that you might have seen on MSP430 before. In these modes everything in the system must be operating at least 32KHz. There is no CPU running although SRAM is detained and you do have RTC watchdog and GPIO active. Those are the possible wake up sources that can wake up and retain the device to active mode. In LPM3 the MSP432 can consume around 850nA. Last but not least, LPM3.5 and LMP4.5 are again similar modes that are borrowed from MSP430. In these modes the entire system is powered down. In LPM3.5, one SRAM bank can actually be retained, however the core logic and everything else is powered down, and you do have the RTC to help you keep track of time. In LPM3.5 you can use RTC interrupt or interrupt to a port pin to wake up the device. In LPM3.5 you can use a reset or a GPIO to return the device to an active state.

7. Power | Software & Intrinsic Support
Blends with Cortex-M sleep & interrupt mechanisms
Go to LPM0/Sleep using Cortex-M CMSIS instructions
__wfi()
Go to LPM3/Deep-Sleep using CMSIS & MSP-DNA intrinsic
__deep_sleep()
DriverLib calls:
PCM_setPowerState() to transitions between all states.
PCM_shutdownDevice(PCM_LPM45);
PCM_gotoLPM0();
PCM_gotoLPM3();
PSS_enableHighSide();
PSS_setHighSidePerformanceMode();
A good thing to remember is that the MSP432 blends really well with the MSP and the Cortex M architecture and it uses the same sleep and wake mechanisms to wake and goes to sleep. There are a number of ways that you can use to instruct the device to go to sleep or wake up. You could either use Cortex M cmsis instructions such as _. You could also use MSP intrinsic conventions such as GoTo LPM0 or GoTo LPM3. In addition to the intrinsic we provide a set of driver library calls that will allow you to move through states very easily. One last thing to remember from this power section and hopefully this is the most important thing you remember is that there is very powerful driver library named PCM_SetPowerSave and this single API can allow you to transition between all available power states within the device. You could use it to change your power modes, changing Vcore as well as changing the regulator from DCDC to LDO and vice versa. So this concludes Part 3 of the MSP432 Training Series. Thanks for watching!