PCA9530_3

© NXP B.V. 2009. All rights reserved.

Product data sheet

Rev. 03 — 26 February 2009

5 of 24

NXP Semiconductors

PCA9530

6.3 Register descriptions

6.3.1 INPUT - Input register

The INPUT register reflects the state of the device pins. Writes to this register will be

acknowledged but will have no effect.

Remark: The default value ‘X’ is determined by the externally applied logic level (normally

6.3.2 PCS0 - Frequency Prescaler 0

PSC0 is used to program the period of the PWM output.

The period of BLINK0 = (PSC0 + 1) / 152.

6.3.3 PWM0 - Pulse Width Modulation 0

The PWM0 register determines the duty cycle of BLINK0. The outputs are LOW (LED on)

when the count is less than the value in PWM0 and HIGH (LED off) when it is greater. If

PWM0 is programmed with 00h, then the PWM0 output is always HIGH (LED off).

The duty cycle of BLINK0 = PWM0 / 256.

6.3.4 PCS1 - Frequency Prescaler 1

PSC1 is used to program the period of the PWM output.

The period of BLINK1 = (PSC1 + 1) / 152.

Table 4.

INPUT - Input register description

Bit

7

6

5

4

3

2

1

0

Symbol

------

LED1

LED0

Default

000000

X

X

Table 5.

PSC0 - Frequency Prescaler 0 register description

Bit

7

6

5

4

3

2

1

0

Symbol

PSC0[7]

PSC0[6]

PSC0[5]

PSC0[4]

PSC0[3]

PSC0[2]

PSC0[1]

PSC0[0]

Default

00000000

Table 6.

PWM0 - Pulse Width Modulation 0 register description

Bit

7

6

5

4

3

2

1

0

Symbol

PWM0

[7]

PWM0

[6]

PWM0

[5]

PWM0

[4]

PWM0

[3]

PWM0

[2]

PWM0

[1]

PWM0

[0]

Default

10000000

Table 7.

PSC1 - Frequency Prescaler 1 register description

Bit

7

6

5

4

3

2

1

0

Symbol

PSC1[7]

PSC1[6]

PSC1[5]

PSC1[4]

PSC1[3]

PSC1[2]

PSC1[1]

PSC1[0]

Default

00000000