Diodes Incorporated PI7C9X1170ACLEX

Overview

PI7C9X1170ACLEX from Diodes Incorporated is an I²C-bus/SPI-to-UART bridge controller with single-channel full-duplex UART, 64-byte TX/RX FIFOs, programmable baud rates up to 16 Mbit/s (4× sampling), and support for RS-232/RS-485/RS-422/IrDA SIR protocols in handheld industrial telemetry systems.

For engineers reviewing the PI7C9X1170ACLEX datasheet, PI7C9X1170ACLEX pinout, PI7C9X1170ACLEX application, or PI7C9X1170ACLEX equivalent, key selection criteria include I²C/SPI interface select logic, GPIO register mapping, FIFO trigger level programmability, and RS-485 auto-direction control via RTS signal.

Technical Context

The PI7C9X1170ACLEX implements a register-compatible extension of the 16C450 UART architecture with dual-mode serial interface selection (I²C slave only or SPI mode 0 slave), fractional baud rate generation using a programmable 16-bit divisor, and independent RX/TX FIFO interrupt trigger levels controlled via FCR and TLR registers.

It integrates hardware flow control (Auto-RTS/CTS) with halt/resume thresholds defined in the Transmission Control Register (TCR), IrDA SIR encoder/decoder supporting 115.2 kbit/s and optional 1.152 Mbit/s, and eight user-programmable GPIO pins with configurable direction and interrupt enable per pin.

Key Specifications

Pinout & Package

PI7C9X1170ACLEX is housed in a 24-pin TQFN (ZD) package with exposed thermal pad; RoHS-compliant, halogen-free, and lead-free construction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar UART bridge applications.

Compared with SC16IS752IPW and MAX3107EAE+T, the PI7C9X1170ACLEX uniquely combines I²C/SPI dual-interface flexibility, RS-485 auto-direction, IrDA SIR, and eight GPIOs in a single 24-pin TQFN-enabling compact, low-component-count designs for battery-operated and industrial edge nodes.

Availability

PI7C9X1170ACLEX is available at Aetrix Electronics and suitable for industrial telemetry gateways, smart meter communication modules, portable HMI terminals, and factory automation edge nodes requiring stable component supply across extended product lifecycles.

Supply support for PI7C9X1170ACLEX includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and integrated circuits, specializing in high-performance analog, logic, and connectivity solutions for industrial, computing, and consumer markets.

The PI7C9X1170 belongs to Diodes' high-integration UART bridge product line, designed specifically to replace legacy 16C450-based designs while adding modern features like dual-interface support, IrDA, and intelligent RS-485 control for space-constrained embedded systems.

FAQ

What interface modes does the PI7C9X1170ACLEX support, and how is mode selection implemented?

The PI7C9X1170ACLEX supports I²C-bus (fast-mode, slave-only) and SPI (mode 0, slave-only) interfaces. Mode selection is determined by the logic level on the dedicated I2C/SPI# pin: HIGH configures I²C operation with A0/A1 setting the 7-bit slave address, while LOW enables SPI mode with A0 functioning as CS# and A1 as SI. This pin must be stable prior to power-up and cannot be changed dynamically during operation.

How does the PI7C9X1170ACLEX implement automatic RS-485 half-duplex direction control?

The device uses the RTS# output pin to drive RS-485 transceiver direction control. When Auto-RTS is enabled, RTS# asserts LOW when the RX FIFO has sufficient space (below halt trigger level) and de-asserts HIGH when the RX FIFO reaches that threshold. Polarity inversion is supported via the Enhanced Features Register, allowing direct connection to transceivers requiring active-HIGH DE signals without external inverters.

Can the PI7C9X1170ACLEX operate with different supply voltages, and what are the implications for I/O compatibility?

Yes-the PI7C9X1170ACLEX operates from 1.62 V to 3.6 V, supporting 1.8 V, 2.5 V, and 3.3 V logic domains. All digital I/O pins (including SDA, SCL, SO, SI, IRQ#, RTS#, CTS#, GPIOs) are fully compatible with the applied VDD voltage, eliminating the need for external level-shifting circuitry when interfacing with mixed-voltage MCUs or peripherals.

What is the role of the Trigger Level Register (TLR), and how does it interact with the FIFO Control Register (FCR)?

The TLR provides programmable RX/TX FIFO interrupt trigger levels (0–63 bytes), overriding the fixed options in the FCR when its bits are non-zero. If TLR is cleared, the FCR's 2-bit trigger select (1/4/8/14 bytes) takes effect. This dual-layer control allows fine-grained latency tuning-for example, setting RX trigger to 32 bytes via TLR for high-throughput streaming while retaining FCR defaults for debug scenarios.