Diodes Incorporated PI7C9X1170BZDE

Overview

PI7C9X1170BZDE from Diodes Incorporated (acquired Pericom) is a single-channel I²C-bus/SPI-to-UART bridge controller with 64-byte TX/RX FIFOs, programmable baud rates up to 16 Mbps (4× sampling), RS-485 auto-direction control via RTS#, and IrDA SIR support up to 1.152 Mbps. It serves as a protocol translation interface between microcontroller I²C/SPI buses and legacy serial peripherals in embedded industrial gateways.

For engineers reviewing the PI7C9X1170BZDE datasheet, PI7C9X1170BZDE pinout, PI7C9X1170BZDE application, or PI7C9X1170BZDE equivalent, key selection criteria include UART register compatibility with 16C450, dual-mode interface select (I²C/SPI), hardware/software flow control implementation, RS-485 half-duplex driver control logic, and GPIO pin multiplexing capability across TSSOP24/QFN24 packages.

Technical Context

The device implements a fully bidirectional bridge architecture where I²C/SPI master devices communicate with UART peripherals using backward-compatible 16C450 register mapping. Its UART core supports fractional baud rate generation via programmable divisor (1–65535), 5–8-bit character length, and configurable stop bits (1/1.5/2) with parity options.

Hardware flow control uses RTS# output and CTS# input with independently programmable halt/resume trigger levels in the Transmission Control Register (TCR); software flow control supports dual Xon/Xoff character sets with configurable comparison logic in the Enhanced Features Register (EFR).

Key Specifications

Pinout & Package

PI7C9X1170BZDE is available in RoHS-compliant 24-pin QFN (4×4 mm) and TSSOP24 packages; both share identical pin mapping except for thermal pad (QFN only). The 16-pin TSSOP variant omits GPIO[3:0] and XTAL2 functionality.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SC16IS752IPW and MAX3107EEG+, PI7C9X1170BZDE uniquely combines I²C/SPI dual-interface support, RS-485 auto-direction, IrDA SIR, and eight GPIOs-making it optimal for space-constrained, multi-protocol edge devices requiring minimal external components.

Availability

PI7C9X1170BZDE is available at Aetrix Electronics and suitable for industrial computing, factory process control, and battery-operated embedded systems requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for PI7C9X1170BZDE 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 acquired Pericom Semiconductor in 2016 and integrates its high-performance interface solutions into broad analog and mixed-signal portfolios targeting industrial, computing, and communications markets.

The PI7C9X1170BZDE belongs to Pericom's legacy UART bridge product line, designed specifically for low-footprint protocol translation in cost-sensitive, power-aware embedded systems interfacing legacy serial peripherals.

FAQ

What interface modes does PI7C9X1170BZDE support, and how is mode selection implemented?

PI7C9X1170BZDE supports I²C-bus (fast-mode, up to 400 kHz) and SPI (mode 0, slave only, up to 20 Mbps) interfaces. Mode selection is controlled by the I2C/SPI# pin: logic HIGH selects I²C operation (activating SDA/SCL), while LOW selects SPI (enabling SO/SI/SCLK/CS#). This pin must be set at power-up and cannot be changed dynamically during operation.

How does the RS-485 auto-direction feature function, and what configuration registers control it?

The RS-485 driver direction is controlled automatically via the RTS# output, which toggles based on RX FIFO occupancy relative to programmable halt/resume thresholds in the Transmission Control Register (TCR). When RX FIFO level falls below the halt threshold, RTS# goes active to enable the driver; when level rises above the resume threshold, RTS# deactivates. Polarity inversion is enabled via the EFR[0] bit.

Can PI7C9X1170BZDE operate from a 1.8 V supply, and what are the implications for I/O voltage levels?

Yes, PI7C9X1170BZDE operates from 1.62 V to 3.6 V, including 1.8 V nominal supply. All digital I/Os (including I²C, SPI, UART, and GPIO) are fully compliant at 1.8 V, with input thresholds scaled accordingly. Pull-up resistors on I²C lines must be adjusted to 1.8 V logic levels (e.g., 1 kΩ for 1.8 V per datasheet guidance), and external peripherals must match the selected VDD voltage.

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

The Trigger Level Register (TLR) provides programmable RX/TX FIFO interrupt trigger points beyond the fixed values in the FIFO Control Register (FCR). If TLR bits are non-zero, they override FCR settings; if cleared, FCR-defined levels (1/4/8/14 bytes) apply. This allows fine-grained interrupt latency tuning-for example, setting RX trigger to 32 bytes to minimize interrupt frequency in high-throughput streaming applications.