Micro-RC Repeater Controller

SOURCE CODE AND DOCUMENTATION

Micro-RC OVERVIEW

What's so special about the uRC controller and why does the world need another repeater controller? Well, this controller is designed using modern SMD chips and components offering a number of onboard features that traditionally required large expensive controllers with hacked on modules for PL, squelch, audio control, etc. Some of the standard uRC features and options include:

• Powerful Atmel ATMega1281 (128K) flashable microcontroller. The ATMega1281 is an advanced RISC type processor operating at 16MHz which allows extensive flexibility for firmware and software options. The CPU provides onboard A/D converters, timer/counters, EPROM, RS232, Flash and SRAM memory and is RTOS capable.
• Extensive full duplex CTCSS encode/decode supporting decode of up to 15 different PL tones. Rx and Tx PL tones can be detected and programmed on the fly under firmware control. Full DCS and inband SelCall tone signaling is also provided.
• Onboard progressive/adaptive SQUELCH processing support. Your receiver only needs to provide a discriminator audio input to the controller - no squelch or PL functions are required at the receiver but may be used if desired. The CPU continuously samples the rx audio discriminator input via an internal CPU A/D converter for real time smart squelch control allowing for advanced noise and drop-out detection algorithms.
• Onboard DTMF decoder for remote control and programming capabilities. The DTMF decoder is interrupt driven by the CPU allowing background processing of DTMF touch tone detect events.
• Onboard industry standard ISD Chip-Corder digital audio voice recorder supporting record and playback of multiple real voice messages with high quality audio.
• Onboard RS232 serial port with full modem control line support. Firmware plans to include remote flash update and extensive remote control/configuration features.
• Optional full backlit 20x2 LCD character display for system status and event display. The LCD display shows all current status and control events in real time.
• Four onboard A/D inputs for 12V power source voltage level, ambient temperature, squelch noise level monitoring and expansion I/O A/D input.
• Dallas RTC clock chip gives full onboard time and date clock support with battery backup.
• Physically small 3x6" board with minimal connections designed to slide into a fully enclosed pocket sized extruded aluminum enclosure. All major audio adjustment trimmers are easily accessible at the board edge.
• Expansion I/O connector for future upgrade daughter cards. Some options may include tx audio/compressor limiter, digital audio delay, external relay and I/O control, SWR monitoring, etc, etc. Pins allow access to the rx-audio insert, tx-audio mixer input, aux audio output, a microcontroller A/D input and digital I/O output lines. Regulated and unregulated power pins are also available.
• Programming headers are included for the Atmel ISP and JTAG programming support. The firmware will support field upgradable updates via bootloader support.
• Four layer full ground plane commercial quality PCB. All circuits are heavily filtered/bypassed and thermal fuse protected. High current MOSFET drivers are provided for FAN and PTT output drivers. Built rugged and well filtered to withstand harsh noise environments.