MSP430 Peripherals
Clocking and Power Management
MSP430 Clocks (Chapter 4)
The MSP430 devices provide a rich, robust set of clocking options.
Rich in that they provide a great number of on- and off-chip clock sources. Further, there are
three internal clocks routed to the CPU and various peripherals. Why three? Simply, there's a
clock for the CPU and two clocks for the peripherals - one fast and the other slow - with goal of
providing the user a balance of performance and low power. Of course, some of the devices
provide more clock choices than others.
Robust clocking in that there are defaults and failsafe’s for all of the various clocks. These failsafe
clocks choices can be particularly important for some applications. Imagine a crystal oscillator
being forcibly removed from the board - or maybe just broken - when your end-product is
accidentally damaged in use. It's nice to know there are internal alternatives that let your product
continue working in a well-documented state.
Please turn to the Clocking chapter for further information.
Power Management
Power is one of those features that every system needs but doesn't often get highlighted. All of
the MSP430 devices provide some level of Power Management. On the most cost-sensitive, it
might only be a Brown-Out Reset (BOR) peripheral - which makes sure there is enough power
going to the device to assure proper, stable operation. The other notable point is that BOR was
designed with extreme sensitivity to low-power system needs.
On other devices you'll find BOR plus an increasing set of power management peripherals. For
example, the 'F5529 device adds an LDO (low dropout voltage regulator) which derives a steady
CPU voltage from that applied to the device. (Normally, voltage regulation is handled by an extra
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