RDS CODER PIRA P132 |
Continuing tests with MRDS1322 RDS coder, attention was directed toward a more advanced model offered by PIRA.CZ: P232 RDS Encoder, built around the PIC18F46K80 microcontroller in a TQFP-44 package.
This is a more complex project, incorporating an internal real-time clock (RTC) with battery backup, output level control via a digital potentiometer, support for multiple interfaces such as RS232, USB, and optionally LAN, and full compatibility with the MagicRDS control software.
Depending on the connected interface, the same coder may appear under different names. The Px32 series—including P132, P232, P232U, and P332 models—consists of similar variants with minor differences in layout and port configurations.
The PIC18F46K80 microcontroller (firmware v2.2) supports the newer RDS2 standard, which uses an additional 66.5 kHz subcarrier to transmit larger data streams. For applications using the classic RDS protocol at 57 kHz, the PCB was specifically designed with this in mind. Supporting RDS2 would require a different output filter and modified PCB layout, known as the P164 version (Px64 series: 164/264/264U/364).
While the PIRA.cz team was helpful and responsive, they declined to share the original PCB layout due to commercial considerations. In response, a visual reverse engineering approach was carried out based on available photographs. Several modifications were introduced, including different heatsink for the voltage regulator, added mounting holes at the corners, removal of the bypass option, and custom I/O connectors.
For communication, a USB–UART connection was implemented using the FTDI FT232 chip. The LAN interface requires a dedicated Nano Socket LAN module, this option was not tested yet.
The "P232" microcontroller is available through the PIRA online shop under RDS Encoders - Components and is priced at approximately €22 plus shipping.
A 16x2 LCD with backlight is supported—ensure pinout compatibility before connecting.
Note: The P132/P232 RDS coder, including its firmware and PC software, is the intellectual property of PIRA.CZ. The contribution here was limited to integrating the microcontroller onto a custom PCB.
P132 Coder schematic (link)
P132 RDS Coder PCB v1 (gerber)
PCB top view
Magic RDS 4 - PC software (link)
Magic RDS Guide (link)
P232 Latest Firmware Upgrade (link), FW update example
P232 MCU datasheet (link), optional RDS2 output filter included
P132 Encoder user manual (link)
P232 Encoder user manual (link)
P232U Encoder user manual (link)
P332 Encoder user manual (link)
P164 Encoder user manual (link)
