Two Serial Ports RS485 and RS232 Stackable HAT for Raspberry Pi
One RS485 and one RS232 drivers connected to Raspberry Pi UARTS 1 and 3; Works with Raspberry Pi 3-5;
Overview
Ultra-compact serial port HAT for Raspberry Pi adding one RS485 and one RS232 port using the Raspberry Pi's native UART interfaces. No additional software required — drivers are included in the Linux kernel. Stackable on top of any other HAT via an extra-tall 2×20 connector. Measures only 93 mm × 14.2 mm.
- RS485 port connected to Raspberry Pi UART1 (GPIO pins 8, 10) — max 921,600 bps
- RS232 port connected to Raspberry Pi UART3 (GPIO pins 32, 33) — max 230,400 bps
- Status LEDs on both serial ports
- Extra-tall 2×20 connector — install on top of any stackable HAT, or under any HAT
- Pluggable connectors accepting 26–16 AWG wires
- Compatible with Raspberry Pi 2 through 5
- No additional software required — drivers included in the Linux kernel
INTERFACES AND I/O
| Serial Ports | To Raspberry Pi | Port Allocation |
|---|---|---|
| • RS485 — max 921,600 bps | • UART1 (GPIO pins 8, 10) | • RS485 → /dev/ttyAMA0
|
| • RS232 — max 230,400 bps | • UART3 (GPIO pins 32, 33) | • RS232 → /dev/ttyAMA4
|
| OTHER FEATURES | ||
| • Status LEDs on both serial ports | ||
| • Extra-tall 2×20 male-female connector — stackable under or on top of any HAT | ||
| • Compact size: 93 mm × 14.2 mm · Pluggable connectors 26–16 AWG | ||
| • No software required — Linux kernel drivers · Compatible with Raspberry Pi 2 through 5 | ||
DESCRIPTION
The latest versions of the Raspberry Pi have up to four UART ports on the GPIO connector, but you cannot use them without a physical layer transceiver.
The Two Serial Ports Card is the perfect solution for connecting your Raspberry Pi to serial devices like sensors and industrial equipment. It supports RS485 and RS232 communication protocols, making it versatile for a wide range of applications. It is probably the smallest HAT in the world, measuring only 93 mm × 14.2 mm.
RS485 Port: Max 921,600 bps
RS232 Port: Max 230,400 bps
Since the card uses the Raspberry Pi UART ports, only one card can be installed per Raspberry Pi. The card's extra-tall 2×20 male-female connector allows it to be installed on top of any stackable HAT. Any Raspberry Pi HAT can also be installed on top of this card.
TECHNICAL DETAILS
CARD LAYOUT
MECHANICAL SPECIFICATIONS
The Two Serial Ports Card is probably the smallest HAT in the world, measuring only 93 mm × 14.2 mm.
COMPATIBILITY
The card is compatible with Raspberry Pi versions from 2 to 5. UART1 (pins 8, 10) is available on all Raspberry Pi cards, so the RS485 port will always work. UART3 may not be available on older versions or on cards that emulate the Raspberry Pi GPIO connector.
POWER REQUIREMENTS
The card takes 5V and less than 40mA of power from the Raspberry Pi GPIO connector.
DOWNLOADS
| User's Guide (PDF) | Schematics (PDF) | CAD | Setup & Documentation |
|---|---|---|---|
| User's Guide V2 | Schematic V1 | 3D STEP Model | |
| Schematic V2 | 3D STEP with Raspberry Pi |
WHAT'S INCLUDED
When you purchase the 2-Serial Ports Card you will receive the following items:
| 1. Two Serial Ports add-on HAT for Raspberry Pi |
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| 2. Mounting Hardware |
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| 4. Connector Plugs |
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