Capture initiated by software, Compare mode – Texas Instruments MSP430x4xx User Manual

Page 221

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Timer_A Operation

12-12

Timer_A

Figure 12−11.Capture Cycle

Second

Capture

Taken

COV = 1

Capture

Taken

No

Capture

Taken

Read

Taken

Capture

Clear Bit COV

in Register TACCTLx

Idle

Idle

Capture

Capture Read and No Capture

Capture

Capture Read

Capture

Capture Initiated by Software

Captures can be initiated by software. The CMx bits can be set for capture on
both edges. Software then sets CCIS1 = 1 and toggles bit CCIS0 to switch the
capture signal between V

CC

and GND, initiating a capture each time CCIS0

changes state:

MOV

#CAP+SCS+CCIS1+CM_3,&TACCTLx ; Setup TACCTLx

XOR

#CCIS0,&TACCTLx

; TACCTLx = TAR

Compare Mode

The compare mode is selected when CAP = 0. The compare mode is used to
generate PWM output signals or interrupts at specific time intervals. When
TAR counts to the value in a TACCRx:

-

Interrupt flag CCIFG is set

-

Internal signal EQUx = 1

-

EQUx affects the output according to the output mode

-

The input signal CCI is latched into SCCI

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