Comparator

The INT6 Flag may also be SET or CLEARed deliberately, at any time, in software. Use the OUT instruction with the associated I/O port address (IFR, address 0x39).

INT7 flag refers to bit 7 within the interrupt flag register. This bit is automatically SET anytime that an INT7 event occurs. This causes the device to branch to the INT7 vector if the associated mask bit is set (IntGenCtrl, address 0x38, bit 7). The INT7 flag is automatically cleared when the device branches to the INT7 vector at 0x7FF7.

The INT7 Flag may also be SET or CLEARed at any time, in software. Use the OUT instruction with the associated I/O port address (IFR, address 0x39).

The TIMER1 enable bit is set or cleared in software: bit 10 of the IntGenCtrl.

Similarly, the falling-edge event in the comparator is a trigger for INT7. This happens independently of any activity associated with TIMER1. TIMER1 can be started by the falling-edge of the comparator. The INT6 flag must be cleared, and the TIMER1 ENABLE must be cleared before the event.

Figure 3–2. Relationship Between Comparator/Interrupt Activity and the TIMER1 Control

INT-Trigger

 

INT Service

 

port-addressed

Event

 

Branch

 

write instruction

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INT Flag bits (IFR)

Associated With the Interrupt-Trigger Event

Interrupt Flag Register (0x39)

0

1

2

3

4

5

 

INT6

 

 

INT7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TIMER1 ENABLE

Bit 10, IntGenCtrl (0x38)

Comparator ENABLE

Bit 15, IntGenCtrl (0x38)

TIMER1 Control 0 = TIM1 stopped 1 = TIM1 running

The comparator, along with all of its associated functions, is enabled by setting bit 15 of the interrupt/general control register (IntGenCtrl, address 0x38). The default value of the register is zero: comparator disabled.

Note: IntGenCtrl Register Bit 15

At the time that bit 15 in the IntGenCtrl is set, PD4 and PD5 become the comparator inputs. At any time during which bit 15 is set, PD4 and PD5 MUST be set to INPUT (I/O Port D Control, address 0x1C, bits 4 and 5 CLEARed). Failure to do so may result in a bus contention.

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Texas Instruments MSP50C6xx manual INT6 INT7 TIMER1 Enable