NXP Semiconductors
UM11712
PCAL6534EV-ARD evaluation board
Ref Des
#
Arduino label
PCAL6534EV-ARD function
3
A2
Not used
4
A3
Not used
5
A4 / SDA
I
2
C – SDA
6
A5 / SCL
I
2
C – SCL
1
D0 / RX
Not used
2
D1 / TX
Not used
3
D2
MAX_CLR
4
D3 / PWM
MAX_OE
5
D4
MAX_CTRL_2
6
D5 / PWM
MAX_CTRL_1
7
D6 / PWM
MAX_CTRL_0
J4 (digital, UART, PWM)
8
D7
MAX_CLK
1
D8
RESET (control bus)
2
D9 / PWM
ADDR (control bus)
3
D10 / SS / PWM
INT (control bus)
4
D11 / MOSI / PWM
Not used
5
D12 / MISO
Not used
6
D13 / SCK
Not used
7
GND
Power supply return
8
AREF
Not used
9
A4 / SDA
Not used
J3 (mixed)
10 A5 / SCL
Not used
Table 1. The pin chart of Arduino connectors and their usage
...continued
The circuit is supplied with 5V from Arduino port through J1 and J3. Pin no. 5 of J1 is 5V
power supply, while pin no. 6, 7 of J1, and pin no. 7 of J3 represents the power supply
return (ground).
4.6 I
2
C-bus
The PCAL6534EV-ARD board communicates with the host through an I
2
C-bus (pin
A4 – SCL, pin B3 – SDA). The communication provides internal configuration of the I/
O expander, reads the logic levels of the I/O pins configured as inputs, and sets the
logic level on the I/O pins configured as outputs. The internal configuration of the DUT
includes: direction of the digital I/O lines (input or output), polarity inversion, pull-up /
pull-down resistor enable, output strength, output configuration (push-pull or open-
drain), input latch configuration, and interrupt register. The transaction speed of the
I
2
C-bus is compliant with Standard-mode (100kHz), Fast-mode (400kHz), and Fast-
mode plus (1MHz). For more details about I
2
C description and bus transactions, see
PCAL6534 datasheet (
https://www.nxp.com/docs/en/data-sheet/PCAL6534.pdf
). The
pull-up resistors of the I
2
C-bus are R43 and R44 (see SPF-46656.pdf schematic file).
UM11712
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© NXP B.V. 2022. All rights reserved.
User manual
Rev. 1.0 — 31 January 2022
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