### Overview of IA82527-PLC44A-R The **IA82527-PLC44A-R** is a high-performance Serial Communications Controller that implements the **CAN (Controller Area Network) Protocol Specification 2.0 (Part A and B)**. It was originally designed by Intel (82527) and is currently manufactured by Innovasic (now part of Analog Devices). --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Protocol Support** | CAN 2.0B (Active), Standard & Extended Frames | | **Interface** | 8-bit Parallel (Multiplexed/Non-multiplexed) | | **Package Type** | PLCC-44 (Plastic Leaded Chip Carrier) | | **Operating Voltage** | 5.0V (Typical) | | **Baud Rate** | Up to 1 Mbps | | **Temperature Range** | Industrial (-40°C to +85°C) | | **Data Buffers** | 15 Message Objects | --- ### 2. Functional Electronic Components The internal architecture of the IA82527 is divided into several functional blocks that manage the complexity of the CAN protocol: #### A. CAN Interface Block This is the "Physical Layer" interface of the chip. It manages the bit-timing logic, synchronization, and the serial stream of data. * **Bit Timing Logic (BTL):** Monitors the bus line and handles the sampling of bits. * **Error Management Unit (EMU):** Handles error detection (stuffing, CRC, form, and acknowledgment errors). #### B. Message Handler and Control Logic This acts as the CPU's representative inside the chip. * It handles the acceptance filtering (deciding which messages are meant for the local node). * It manages the transfer of data between the CAN bus and the Message Objects. #### C. Message Memory (RAM) The chip contains dedicated RAM to store **15 Message Objects**. * **Objects 1-14:** Can be configured for either transmission or reception. * **Object 15:** Specifically designed for receive-only with double buffering to prevent data loss during high-traffic periods. #### D. Microprocessor Interface (MPI) The IA82527 is designed to be a peripheral to a microcontroller (like an 8051 or 68HC11). * It supports **Multiplexed** address/data buses. * It supports **Non-multiplexed** 8-bit buses. * It includes a **Serial Interface Mode** (SPI-like) for systems with low pin counts. --- ### 3. Pin Configuration Highlights (PLCC-44) The "PLC44" in the part number refers to the 44-pin Plastic Leaded Chip Carrier. Key pins include: | Pin Name | Function | Description | | :--- | :--- | :--- | | **AD0 - AD7** | Address/Data Bus | 8-bit bidirectional bus for communication with the MCU. | | **TX0 / TX1** | CAN Transmit | Output pins to the CAN transceiver. | | **RX0 / RX1** | CAN Receive | Input pins from the CAN transceiver. | | **XTAL1 / XTAL2** | Oscillator | Input for the crystal or external clock circuit. | | **INT** | Interrupt | Signals the MCU when a message is received or an error occurs. | --- ### 4. Implementation Context To use this part in a real-world circuit, you generally need the following surrounding components: 1. **CAN Transceiver:** The IA82527 provides logic-level signals. You need a transceiver (like an MCP2551 or TJA1050) to convert these to the differential signals used on the CAN bus. 2. **Termination:** A $120\Omega$ resistor at the ends of the CAN bus. 3. **Host MCU:** A microcontroller to initialize the registers and process the data.