PCA9535CD datasheet(8/32 Pages) NXP

8 / 32 page

PCA9535_PCA9535C_3

Product data sheet

Rev. 03 — 4 October 2007

8 of 32

NXP Semiconductors

PCA9535; PCA9535C

16-bit I2C-bus and SMBus, low power I/O port with interrupt

6.2.5 Registers 6 and 7: Conﬁguration registers

This register conﬁgures the directions of the I/O pins. If a bit in this register is set (written

with ‘1’), the corresponding port pin is enabled as an input with high-impedance output

driver. If a bit in this register is cleared (written with ‘0’), the corresponding port pin is

enabled as an output. At reset, the device's ports are inputs.

6.3 Power-on reset

When power is applied to VDD, an internal power-on reset holds the PCA9535/PCA9535C

in a reset condition until VDD has reached VPOR. At that point, the reset condition is

released and the PCA9535/PCA9535C registers and SMBus state machine will initialize

to their default states. Thereafter, VDD must be lowered below 0.2 V to reset the device.

For a power reset cycle, VDD must be lowered below 0.2 V and then restored to the

operating voltage.

6.4 I/O port

When an I/O is conﬁgured as an input on PCA9535, FETs Q1 and Q2 are off, creating a

high impedance input. The input voltage may be raised above VDD to a maximum of 5.5 V.

In the case of PCA9535C, FET Q1 has been removed and the open-drain FET Q2 will

function the same as PCA9535.

If the I/O is conﬁgured as an output, then on PCA9535 either Q1 or Q2 is on, depending

on the state of the Output Port register. Care should be exercised if an external voltage is

applied to an I/O conﬁgured as an output because of the low-impedance path that exists

between the pin and either VDD or VSS.

Table 11.

Conﬁguration port 0 register

Bit

Symbol

C0.7

C0.6

C0.5

C0.4

C0.3

C0.2

C0.1

C0.0

Default

11111111

Table 12.

Conﬁguration port 1 register

Bit

Symbol

C1.7

C1.6

C1.5

C1.4

C1.3

C1.2

C1.1

C1.0

Default

11111111

PCA9535CD Datasheet(PDF) 8 Page - NXP Semiconductors

PCA9535CD Datasheet(HTML) 8 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Datasheet Download

Link URL