AT78C1502

Features:

• Servo Processing Unit (SPU), Using Dedicated 16-bit Instruction Cycle AVR^® RISC Cores (3), Giving 120 MIPS Maximum Processing Power with 40 MHz SYSCLK
• SPU Includes 17 x 17 Single-clock Cycle MAC
• On-chip Debugger Monitor for Program Development (OCDM)
• 8K Words Program RAM
• 4K Bytes Data RAM
• On-chip Clock Frequency Synthesizer with Output Clock Buffers for AT78C1501 Controller
• On-chip S/H and WCS Timing State Machine (TSM) for Conversion of Focus, Tracking and SUM Signals
• 10-bit 1.2 µsec ADC with six-channel MUX
• Synchronized ADC Conversions with SPU Interrupt Service Routine
• Three Fast 10-bit 500 nsec (rise time) DACs for Servo Loops and Adjustments
• Three 8-bit DACs for Offset Adjustment and Spin Loop
• Bandgap ADC and DAC Midpoint Reference Outputs
• SPU Implemented Spindle Speed Control
• Spindle Interface Logic and Hardware Support for Both CAV and CLV Spindle Control Modes
• Eight General Purpose I/O Pins
• SPU Servo Control of Focus, Fine Track, Coarse Track and Tray Load Motors
• High-speed Track Counter for Accurate High-speed Track Counts (1.4 MHz when used with AT78C1503 Read Channel)
• Lower Power Operations with 3.3V Core and 5V Tolerant I/Os
• 8-bit Data and 14-bit Address Controller/Microprocessor Interface
• 3-pin Universal Serial Port Interface to Program Read Channel and Power Devices
• Power Management
• On-chip UART to Access OCDM Unit



Pinout




Description

The Atmel AT78C1502 high-performance servo controller fully integrates all of the control and demodulation fun-ctions for DVD and CD, optical/mechanical systems. Packaged in 128-lead TQFP and fabricated in 0.35 micron CMOS, the device operates on a 3.3V logic/analog supply and provides 5V tolerance for digital I/O. An AVRbased Servo Processing Unit (SPU) embedded in the device provides programmable control of spindle speed, coarse and fine tracking, focus, sled, draw motor and tilt. The three parallel programmable AVR microcontrollers in the SPU are the heart of the system, offering a range of servo sample rates. With only a 40 MHz system clock, 120 MIPS of pro-cessing power is provided. Real-time notch filters can also be calculated. Fast 10-bit DACs provide real-time control of servo loops and other system adjustments. A universal serial port and many general purpose I/Os are provided.

AVR0 is the master AVR of the three microcontrolloers, communicating with AVR1, AVR2 and the ARMTDMI in the AT78C1502 interface controller and to the AT78C1503 read channel. An On-Chip Debugger Monitor (OCDM) is offered to enable programmers to easily observe theeffect of changes to code on each AVR.

System-level evaluation boards are available with development code in both C and native code for basic operation of all servos. Simple changes to the code allow any mechadeck to be interfaced to the AT78C1502.