NXP Semiconductors PCAL6408A-ARD, User Manual, Page: 8 / 25

NXP Semiconductors
UM11704
PCAL6416AEV-ARD evaluation board
Ref Des # Arduino label PCAL6416AEV-ARD function
6 A5 / SCL I
2
C – SCL
1 D0 / RX Not used
2 D1 / TX Not used
3 D2 Not used
4 D3 / PWM Not used
5 D4 Not used
6 D5 / PWM Not used
7 D6 / PWM Not used
J4 (digital, UART, PWM)
8 D7 Not used
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. Pin chart of Arduino connectors
...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 PCAL6416A communicates with the host through an I
2
C bus (pin A5 – SCL, pin A4
– 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), and Fast-mode (400kHz). For more details about I
2
C description and
bus transactions, see PCAL6416A datasheet (NXP Semiconductors). The pull-up
resistors of the I
2
C bus are R2 and R3 (see SPF-46663.pdf schematic file).
4.7 Control bus
The control bus manages the RESET, ADDR, and INT pins of the PCAL6416A IC. The
RESET pin is digital input and is controlled by the system host. Its role is to reset the I/
O expander when a time-out or other improper operation occurs. Asserting a low level of
this line forces a reset operation of the internal control section of the IC (puts the internal
UM11704 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2021. All rights reserved.
User manual Rev. 1.0 — 1 December 2021
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