Motorola MCF5281, MCF5282 GPT System Control Register 2 GPTSCR2, Gptie Field Descriptions

Models: MCF5282 MCF5281

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Memory Map and Registers

 

 

Table 20-13. GPTIE Field Descriptions

 

 

 

 

 

Bit(s)

Name

 

Description

 

 

 

 

 

7–4

Reserved, should be cleared.

 

 

 

 

 

3–0

CnI

Channel interrupt enable. Enables the C[3:0]F flags in GPT flag register 1 to generate

 

 

 

interrupt requests for each channel. These bits are read anytime, write anytime.

 

 

 

1

Corresponding channel interrupt requests enabled

 

 

 

0

Corresponding channel interrupt requests disabled

 

 

 

 

 

 

20.5.11 GPT System Control Register 2 (GPTSCR2)

Field

Reset

R/W

Address

7

6

5

4

3

2

0

TOI

PUPT

RDPT

TCRE

 

PR

 

 

 

 

 

 

 

0000_0000

R/W

IPSBAR + 0x1A_000D, 0x1B_000D

Figure 20-13. GPT System Control Register 2 (GPTSCR2)

Table 20-14. GPTSCR2 Field Descriptions

 

Bit(s)

Name

 

 

Description

 

 

 

 

 

 

 

7

TOI

Enables timer overflow interrupt requests.

 

 

 

 

1

Overflow interrupt requests enabled

 

 

 

 

0

Overflow interrupt requests disabled

 

 

 

 

 

 

 

6

Reserved, should be cleared.

 

 

 

 

 

 

 

5

PUPT

Enables pull-up resistors on the GPT ports when the ports are configured as inputs.

 

 

 

 

1

Pull-up resistors enabled

 

 

 

 

0

Pull-up resistors disabled

 

 

 

 

 

 

 

4

RDPT

GPT drive reduction. Reduces the output driver size.

 

 

 

 

1

Output drive reduction enabled

 

 

 

 

0

Output drive reduction disabled

 

 

3

TCRE

Enables a counter reset after a channel 3 compare.

 

 

 

 

1

Counter reset enabled

 

 

 

 

0

Counter reset disabled

 

 

 

 

Note: When the GPT channel 3 registers contain 0x0000 and TCRE is set, the GPT

 

 

 

 

counter registers remain at 0x0000 all the time. When the GPT channel 3 registers

 

 

 

 

contain 0xFFFF and TCRE is set, TOF does not get set even though the GPT counter

 

 

 

 

registers go from 0xFFFF to 0x0000.

 

 

2–0

PRn

Prescaler bits. Select the prescaler divisor for the GPT counter.

 

 

 

 

000

Prescaler divisor 1

 

 

 

 

001

Prescaler divisor 2

 

 

 

 

010

Prescaler divisor 4

 

 

 

 

011

Prescaler divisor 8

 

 

 

 

100

Prescaler divisor 16

 

 

 

 

101

Prescaler divisor 32

 

 

 

 

110

Prescaler divisor 64

 

 

 

 

111

Prescaler divisor 128

 

 

 

 

Note: The newly selected prescaled clock does not take effect until the next

 

 

 

 

synchronized edge of the prescaled clock when the clock count transitions to 0x0000.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MOTOROLA

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

20-11

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Motorola MCF5281, MCF5282 user manual GPT System Control Register 2 GPTSCR2, Gptie Field Descriptions