Texas Instruments MSP430x1xx manual 14. Output Example-Timer in Up/Down Mode

Timer_B Operation

Output Example − Timer in Up/Down Mode

The OUTx signal changes when the timer equals TBCLx in either count direction and when the timer equals TBCL0, depending on the output mode. An example is shown in Figure 12−14 using TBCL0 and TBCL3.

Figure 12−14. Output Example—Timer in Up/Down Mode

TBR(max)
TBCL0
TBCL3
0h
						Output Mode 1: Set
						Output Mode 2: Toggle/Reset
						Output Mode 3: Set/Reset
						Output Mode 4: Toggle
						Output Mode 5: Reset
						Output Mode 6: Toggle/Set
						Output Mode 7: Reset/Set
	EQU3	EQU3		EQU3	EQU3	Interrupt Events
TBIFG	EQU0		TBIFG	EQU0

Note: Switching Between Output Modes

When switching between output modes, one of the OUTMODx bits should remain set during the transition, unless switching to mode 0. Otherwise, output glitching can occur because a NOR gate decodes output mode 0. A safe method for switching between output modes is to use output mode 7 as a transition state:

BIS	#OUTMOD_7,&TBCCTLx ;	Set output mode=7
BIC	#OUTMODx,&TBCCTLx ;	Clear unwanted bits

Timer_B 12-17