Reset

 

 

 

Table 20-23. GPT Settings and Pin Functions (continued)

 

 

 

 

 

 

 

 

 

 

 

1

1

1

 

X

<> 0

0

Out

OC action

Output compare

Pin driven by OC action(5)

1

0

1

 

X

X

1

Out

OC action/

Output compare

Pin readable only if DDR = 0 6

 

 

 

 

 

 

 

 

OC3Dn

(ch 3)

 

 

 

 

 

 

 

 

 

 

 

 

1

1

1

 

X

X

1

Out

OC action/

Output compare/

Pin driven by channel OC action and

 

 

 

 

 

 

 

 

OC3Dn

OC3Dn

OC3Dn via channel 3 OC(6)

 

 

 

 

 

 

 

 

 

(ch 3)

 

 

 

 

 

 

 

 

 

 

 

 

1When DDR set the pin as input (0), reading the data register will return the state of the pin. When DDR set the pin as output (1), reading the data register will return the content of the data latch. Pin conditions such as rising or falling edges can trigger an input capture on a pin configured as an input.

2OMn/OLn bit pairs select the output action to be taken as a result of a successful output compare. When either OMn or OLn is set and the IOSn bit is set, the pin is an output regardless of the state of the corresponding DDR bit.

3Setting an OC3M bit configures the corresponding PORTTn pin to be output. OC3Mn makes the PORTTn pin an output regardless of the data direction bit when the pin is configured for output compare (IOSn = 1). The OC3Mn bits do not change the state of the PORTTnDDR bits.

4X = Don’t care

5An output compare overrides the data direction bit of the output compare pin but does not change the state of the data direction bit. Enabling output compare disables data register drive of the pin.

6A successful output compare on channel 3 causes an output value determined by OC3Dn value to temporarily override the output compare pin state of any other output compare channel.The next OC action for the specific channel will still be output to the pin. A channel 3 output compare can cause bits in the output compare 3 data register to transfer to the GPT port data register, depending on the output compare 3 mask register.

20.7 Reset

Reset initializes the GPT registers to a known startup state as described in Section 20.5, “Memory Map and Registers.”

20.8 Interrupts

Table 20-24lists the interrupt requests generated by the timer.

Table 20-24. GPT Interrupt Requests

Interrupt Request

Flag

Enable Bit

 

 

 

Channel 3 IC/OC

C3F

C3I

 

 

 

Channel 2 IC/OC

C2F

C2I

 

 

 

Channel 1 IC/OC

C1F

C1I

 

 

 

Channel 0 IC/OC

C0F

C0I

 

 

 

PA overflow

PAOVF

PAOVI

 

 

 

PA input

PAIF

PAI

 

 

 

Timer overflow

TOF

TOI

 

 

 

MOTOROLA

Chapter 20. General Purpose Timer Modules (GPTA and GPTB)

20-21

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Image 443
Motorola MCF5281, MCF5282 Reset, Interrupts, 24lists the interrupt requests generated by the timer, GPT Interrupt Requests