Diodes Incorporated PI7C9X762BZHE

Overview

PI7C9X762BZHE from Diodes Incorporated is a dual-channel, full-duplex I²C-bus/SPI-to-UART bridge controller with 64-byte TX/RX FIFOs per channel, programmable baud rates up to 16 Mbit/s (4× sampling), hardware/software flow control, and RS-485 driver direction control via RTS. It operates from 1.8 V, 2.5 V, or 3.3 V and supports industrial temperature range (−40 °C to +85 °C) in TQFN32 package - used in embedded industrial gateways for protocol translation between microcontrollers and legacy serial peripherals.

For engineers reviewing the PI7C9X762BZHE datasheet, PI7C9X762BZHE pinout, PI7C9X762BZHE application, or PI7C9X762BZHE equivalent, key selection criteria include dual UART channel independence, I²C/SPI interface mode selection, GPIO programmability, RS-485 auto-direction control, and compatibility with 16C450 register mapping for firmware reuse.

Technical Context

The PI7C9X762BZHE implements two independent UART channels (A and B), each with fully programmable framing (5–8 bit, parity, stop bits), fractional baud rate generation, and separate 64-byte FIFOs with configurable trigger levels. Its register set is backward-compatible with the industry-standard 16C450, enabling drop-in firmware integration.

It supports dual interface modes: I²C-bus slave (fast-mode, up to 400 kHz) with address select via A0/A1 pins, or SPI slave (mode 0, up to 33 MHz) with chip-select and 3-state SO output. Clock input accepts either crystal (up to 24 MHz) or external clock (up to 64 MHz), and includes built-in IrDA SIR encoder/decoder supporting 115.2 kbit/s and optional 1.152 Mbit/s.

Key Specifications

Pinout & Package

PI7C9X762BZHE is housed in a 32-pin TQFN package (5 mm × 5 mm, 0.5 mm pitch) with exposed thermal pad connected to VSS. Pin functions are mode-dependent (I²C vs. SPI); critical shared signals include dual UART I/O (RXA/TXA/RTSA/CTSA, RXB/TXB/RTSB/CTSB), interrupt (IRQ), reset (RESET), clock inputs (XTAL1/XTAL2), and eight GPIOs mapped to modem control roles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SC16IS752IPW and MAX3107EEG+, the PI7C9X762BZHE uniquely delivers dual UARTs with both I²C and SPI interface options, RS-485 auto-direction, and 8 GPIOs - making it the only solution that consolidates protocol bridging, bus control, and peripheral expansion in one TQFN32 device.

Availability

PI7C9X762BZHE is available at Aetrix Electronics and suitable for industrial computing, factory automation, and embedded networking applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PI7C9X762BZHE 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, energy-efficient solutions for industrial, computing, and communications markets.

The PI7C9X762 belongs to Diodes' UART bridge controller product line, designed specifically to simplify serial interface expansion in resource-constrained embedded systems while maintaining full register compatibility with legacy 16C450-based firmware stacks.

FAQ

What interface modes does PI7C9X762BZHE support, and how is mode selection implemented?

The PI7C9X762BZHE supports both I²C-bus slave (fast-mode, up to 400 kHz) and SPI slave (mode 0, up to 33 MHz). Mode selection is controlled by the I2C/SPI pin: logic HIGH selects I²C mode (activating SDA/SCL), logic LOW selects SPI mode (activating SI/SO/SCLK/CS). This pin must be hardwired during PCB design and cannot be changed dynamically in operation.

How does the PI7C9X762BZHE handle RS-485 half-duplex bus direction control?

The device provides automatic RS-485 driver direction control using the RTSA/RTSB outputs. When enabled via the Enhanced Features Register, RTS asserts before transmission and deasserts after completion. Polarity inversion is supported via a dedicated register bit, allowing direct connection to standard RS-485 transceivers (e.g., MAX13487) without external logic gates or inverters.

Can the 8 GPIO pins be used simultaneously as both modem control signals and general-purpose I/O?

No - each GPIO pin (GPIO0–GPIO7) has dual function mapping (e.g., GPIO4/DSRA), but only one role is active at a time. Configuration is done via the GPIO Control Register: setting a pin as "modem mode" enables DSR/DTR/CD/RI behavior with automatic status reporting; setting it as "GPIO mode" enables read/write access and interrupt generation, but disables modem signaling logic.

What is the maximum crystal frequency supported for internal oscillator operation?

The PI7C9X762BZHE supports crystal frequencies up to 24 MHz across XTAL1/XTAL2. For higher timing precision or non-integer baud rates, an external clock source up to 64 MHz may be applied to XTAL1, bypassing the crystal oscillator circuit entirely. The internal PLL is not present; baud rate generation relies solely on divisor-based division of the selected clock source.