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Texas Instruments MSP50C6xx User Manual

Page 81

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Comparator

3-17

Peripheral Functions

The function of pins PD

4

and PD

5

, and the behavior of events COND2, INT6,

INT7, and TIMER1 are different, depending on whether the comparator has
been enabled or disabled. A summary of the various states appears in the fol-
lowing table:

Comparator ENABLED

SET bit 15 in the IntGenCtrl, address 0x38 . . .

PD

4

functions as comparator negative input

PD

5

functions as comparator positive input

(port D Control, 0x1C, bit 4 MUST be 0)
(port D Control, 0x1C, bit 5 MUST be 0)

COND2 maps to the state of the comparator

(PD

5

relative to PD

4

)

INT6 is triggered by PD

5

rising above PD

4

INT7 is triggered by PD

5

falling below PD

4

(IntGenCtrl, 0x38, bit 6 must be 1)
(IntGenCtrl, 0x38, bit 7 must be 1)

TIMER1 may be started by PD

5

rising above PD

4

TIMER1 will be stopped by PD

5

falling below PD

4

(assuming TIMER1 Enable is 0 and INT6
flag is 0)
(assuming TIMER1 Enable is 0 and INT7
flag is 1)

Comparator DISABLED

CLEAR bit 15 in the IntGenCtrl, address 0x38 . . .

PD

4

functions as a general-purpose I/O pin

PD

5

functions as a general-purpose I/O pin

(See Section 3.1.1)
(See Section 3.1.1)

COND2 maps to the state of the I/O pin PD

1

(See Section 3.1.4)

INT6 is triggered by a rising edge at PD

4

INT7 is triggered by a falling edge at PD

5

(IntGenCtrl, 0x38, bit 6 must be 1)
(IntGenCtrl, 0x38, bit 7 must be 1)

TIMER1 is started/stopped in software by setting/clearing TIMER1 enable
(IntGenCtrl, 0x38, bit 10)