86
Timer Overview
There are several types of timers in MSP430 micros. These include Watchdog Timer (WDT), Real Time
Clock (RTC), Basic Timer 1 and Timer A and Timer B. Timer As and Bs are general purpose 16-bit timers
that are suitable for time base generations, pulse width modulations (PWM) and input captures. The
other three types have special uses and their names suggest their purposes. All MSP430 devices have
at least one Timer A module and a WDT module. Since both are common amongst all devices, we will
be studying about them here. Timer As and Bs are almost same. The difference between the two is
the presence of some additional features like more Capture/Compare (CC) channels in Timer Bs.
Timer A
In TI’s literature, timers are named like Timer0_A3, Timer_B7, etc. A number can be present right after
the word Timer in some case and in other cases, it may be absent. This number is present whenever
there are multiple timers of same type in a MSP430 micro. For example, there are two Timer A3s in
MSP430G2553 micros and so they are labelled as Timer0_A3 and Timer1_A3. The other number in
the timer’s name after the timer type letter denotes the number of CC channels available with it.
Shown below is the block diagram of Timer A module. MSP430G2452 has one and MSP430G2553 has
two Timer A3 modules. Typically, in any micro’s timer we would expect two things - first a counter
block (highlighted in purple) and second CC modules (highlighted in green). As we can see the CC
channels share the same TAR register and so they share the similar properties.
To Next Page
Loading...
Need help?
General
