# I2C Protocol Definition — UVM TB Generator
protocol: i2c
description: Inter-Integrated Circuit
tags: [serial, synchronous, multi-master, open-drain]

interface_template:
  signals:
    - {name: scl, direction: inout, width: 1, description: Serial clock line}
    - {name: sda, direction: inout, width: 1, description: Serial data line}

config_parameters:
  - {name: SLAVE_ADDR, type: int, default: 0x50, minimum: 0x00, maximum: 0x7F, description: 7-bit slave address}
  - {name: CLK_FREQ,   type: int, default: 100000, description: I2C bus frequency (Hz)}
  - {name: ADDR_WIDTH, type: int, default: 7, enum: [7, 10], description: Addressing mode}

register_template:
  - name: CR      # Control Register
    address: 0x00
    access: rw
    fields:
      - {name: enable,    bits: 0, description: I2C core enable}
      - {name: irq_en,    bits: 1, description: Interrupt enable}
      - {name: addr_mode, bits: 2, description: 0=7bit, 1=10bit}
  - name: ADR     # Slave Address Register
    address: 0x04
    access: rw
    fields:
      - {name: addr, bits: 9:0, description: Slave address}
  - name: DR      # Data Register
    address: 0x08
    access: rw
    fields:
      - {name: data, bits: 7:0, description: I2C data byte}
  - name: SR      # Status Register
    address: 0x0C
    access: ro
    fields:
      - {name: busy,    bits: 0, description: Bus busy}
      - {name: rx_ack,  bits: 1, description: Receive acknowledge}
      - {name: tx_rdy,  bits: 2, description: TX ready}
      - {name: rx_rdy,  bits: 3, description: RX ready}
      - {name: arb_lost,bits: 4, description: Arbitration lost}
      - {name: nack,    bits: 5, description: No acknowledge received}

sequence_template:
  name: i2c_sequence
  body: |
    // I2C write sequence
    drv.write_reg(ADR, slave_addr);
    drv.write_reg(CR, {1'b1, enable});
    foreach (tx_data[i]) begin
      drv.write_reg(DR, tx_data[i]);
      drv.wait_for_field(SR, tx_rdy, 1);
    end

coverage_template:
  - name: i2c_cg
    type: covergroup
    items:
      - {name: cg_addr,  type: coverpoint, expression: slave_addr}
      - {name: cg_dir,   type: coverpoint, expression: {read, write}}