SH7021 datasheet(287/509 Pages) RENESAS

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RENESAS 271

Buffer Transfers when Changing from Increment to Decrement: When the contents of the GR

are within GRA3 – T + 1 and GRA3, do not transfer a value outside this range. When the contents

of GR are outside this range, do not a transfer a value within it. Figure 10.39 illustrates a point of

caution regarding changing of GR settings with a buffer operation.

GRA3 + 1

GRA3

GRA3 – T + 1

GRA3 – T

TCNT3

TCNT4

Changes inhibited

Figure 10.39 Caution for Changing GR Settings with Buffer Operation (1)

Buffer Transfers when Changing from Decrement to Increment: When the contents of the GR

are within H'0000 to T–1, do not transfer a value outside this range. When the contents of GR are

outside this range, do not transfer a value within it. Figure 10.40 illustrates this point of caution

regarding changing of GR settings with a buffer operation

TCNT4

T – 1

H' 0000

H' FFFF

TCNT3

Changes inhibited

Figure 10.40 Caution for Changing GR Settings with Buffer Operation (2)

When GR Settings are Outside the Count Range (H'0000–GRA3): Waveforms of duty cycle

0% and 100% can be output by setting GR outside the count area. Be sure to make the direction of

the count (increment/decrement) when writing a setting from outside the count area into the buffer

count area in the BR.

SH7021 Datasheet(PDF) 287 Page - Renesas Technology Corp