UPD17231 datasheet(45/94 Pages) RENESAS

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Data Sheet U14360EJ1V0DS00

µPD17230, 17231, 17232, 17233, 17234, 17235, 17236

Setting carrier frequency and duty factor

Where the system clock frequency is fX, carrier frequency is fC, and carrier generation clock is RfX:

•

When RfX = fX/2:

(division ratio) = fX/(2

× fC)

•

When RfX = fX :

(division ratio) = fX/fC

is divided into m:n and is set in the modulo registers as follows:

High-level period set value = {

× m/(m + n)} – 1

Low-level period set value = {

× n/(m + n)} – 1

Example

Where fC = 38 kHz, duty factor (high-level period) = 1/3, fX = 4 MHz, and RfX = fX/2:

= 4 MHz/(2

× 38 kHz) = 52.6

m:n = 1:2

From the above, the value of the modulo register is:

High-level period = 17

Low-level period = 34

Therefore, the carrier frequency is 37.74 kHz.

Table 5-1. Carrier Frequency List

(1) Where fX = 4 MHz and RfX = fX/2

Set Value

tH (

µs)

tL (

µs)

1/fC (

µs)

fC (kHz)

Duty

NRZHTMM

NRZLTMM

00H

0.5

1.0

1000

1/2

01H

02H

1.0

1.5

2.5

400

2/5

04H

2.5

5.0

200

1/2

09H

5.0

10.0

100

1/2

0FH

10H

8.0

16.5

60.6

1/2

0FH

21H

8.0

17.0

25.0

40.0

1/3

11H

21H

9.0

17.0

26.0

38.5

1/3

11H

22H

9.0

17.5

26.5

37.7

1/3

19H

35H

13.0

27.0

40.0

25.0

1/3

3FH

32.0

64.0

15.6

1/2

7FH

64.0

120.0

7.8

1/2

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