Diodes Incorporated
Back to UART - Universal Asynchronous Receiver / Transmitter


I2C/SPI to Single UART Bridge Controller

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The PI7C9X1170 is a I2C-bus/SPI to a single-channel high performance UART bridge controller. It offers data rates up to 33Mbps and guarantees low operating and sleeping current. The PI7C9X1170 also has up to 8 additional programmable general purpose I/O [GPIO] pins. The device comes in very small TSSOP24 and TSSOP16 packages, which makes it ideally suitable for cost efficient, handheld, battery operated applications. These UART bridges provide protocol conversion from I2C -bus or SPI to RS-232/RS-485/RS-422 and are fully bidirectional. The PI7C9X1170 supports SPI clock speeds up to 33Mbps and IrDA SIR up to 1.152Mbit/s.

PI7C9X1170’s internal register set is backward-compatible with the widely used and widely popular 16C450 UART.

The PI7C9X1170 also provides additional advanced features such as auto hardware and software flow control, automatic RS-485 support, support for fractional baud rates and software reset. This allows the software to reset the UART at any moment, independent of the hardware reset signal. This allows the software to reset the UART at any moment, independent of the hardware reset signal.


  • Single channel full-duplex UART
  • Support I2C-bus or SPI interface
  • 64 bytes FIFO (transmitter and receiver)
  • Fully compatible with industrial standard 16C450 and equivalent
  • Baud Rates up to 16Mbit/s in 4X sampling clock rate
  • Programmable character formatting
    • 5-bit, 6-bit, 7-bit or 8-bit character
    • Even, odd, or no parity
    • 1, 1.5, or 2 stop bits
  • Programmable Receive and Transmit FIFO trigger levels
  • Special character detection
  • Internal Loopback mode
  • Line break generation and detection

Flow Control

  • Support hardware flow control using RTS/CTS
  • Support software flow control with programmable Xon/Xoff characters
  • Programmable single or double Xon/Xoff characters

Interface Control

  • Automatic RS-485 slave address detection
  • RS-485 driver direction control via RTS signal
  • RS-485 driver direction control inversion
  • Built-in IrDA encoder and decoder interface
  • Supports IrDA SIR with speeds up to 115.2kbit/s (optional 1.152Mbps)
  • Up to eight user programmable GPIO pins
  • Software reset


  • Low standby current at 3.3V
  • Wide operation voltage (1.8V, 2.5V or 3.3V)
  • Industrial and commercial temperature ranges
  • Available in QFN24, TSSOP24 and TSSOP16 Packages

I2C Interface

  • Compliant with I2C-bus fast speed
  • Support slave mode only
  • Crystal oscillator (up to 24MHz) or external clock (up to 64MHz) input

SPI Interface

  • PI7C9X1170 supports 33 Mbit/s maximum SPI clock speed
  • Support SPI mode 0 (slave mode only)
  • Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
  • Halogen and Antimony Free. “Green” Device (Note 3)
  • For automotive applications requiring specific change control (i.e. parts qualified to AEC-Q100/101/104/200, PPAP capable, and manufactured in IATF 16949 certified facilities), please contact us or your local Diodes representative. https://www.diodes.com/quality/product-definitions/
  • Packaging (Pb-free & Green):
    • 16-pin, TSSOP (L)
    • 24-pin, TSSOP (L)
    • 24-pin, TQFN (ZD)


  • Industrial Computing
  • Automation
  • Factory Process Control
  • Mobile Computing
  • Embedded Applications
  • Battery Operated Devices
  • Networking

Product Specifications

Product Parameters

Ports 1 UART
Pins 16,24
Data Rate (kbps) 16Mbps
Bytes 64
Tx/Rx FIFO Ctrs Yes
Tx/Rx FIFO INT Trig Yes
Auto RTS/CTS Yes
Interface I2C/SPI
Ambient or Junction Temperature (°C) -40 to 85

Technical Documents

Recommended Soldering Techniques


Additional Technical Documents are available upon request:
Application information, Evaluation board, and Other technical documents

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Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN # Issue Date Implementation Date Subject
PCN-2510 2021-02-26 2021-05-26 Qualified Additional A/T Sites, Fab Site and Data Sheet Change
PCN-2328 2018-04-12 2018-10-12 Device End of Life for tray packaging only