Overview

Features

This LSI is a single-chip RISC microprocessor that integrates a 32-bit RISC-type Super H architecture CPU with a digital signal processing (DSP) extension as its core, together with a large-capacity 32-kbyte cache memory, a 16-kbyte X/Y memory, and an interrupt controller. High-speed data transfers can be performed by an on-chip direct memory access controller (DMAC), and an external memory access support function enables direct connection to different kinds of memory. This LSI also supports a stereo audio recording and playback function, a USB host controller, a function controller, an LCD controller, a PCMCIA interface, an A/D converter, and a D/A converter.

The USB host controller and LCD controller have bus master functions, so that data supplied from an external memory (area 3) can be freely processed. Since the USB host controller, in particular, conforms to Open HCI standards, it is extremely easy to transfer data from the PC of a device driver or other devices. Also, low-power operation suitable for battery operation is possible because the LCD controller continues to display even in sleep mode.

A powerful built-in power management function keeps power consumption low, even during high speed operation. This LSI is ideal for electronics devices, which require both high speed and low power consumption.

The SH7720 group integrates an SSL (Secure Socket Layer) accelerator that performs RSA (Rivest-Shamir-Adleman) operations and DES (Data Encryption Standard) and Triple-DES encryption/decryption, while the SH7721 group does not have the SSL accelerator. Each group consists of several models which includes or does not include an SD host interface (SDHI) to be suited to a variety of applications. See table 1.2 and 1.3, Product Lineup, for the models including (or not including) the SDHI.

SH7720/SH7721 Features

Features

CPU

• Renesas Technology Original SuperH architecture

• Upper compatibility with SH-1, SH-2, and SH3-DSP at object code level

• 32-bit internal data bus

• General-register

 Sixteen 32-bit general registers (eight 32-bit shadow registers)

 Five 32-bit control registers

 Four 32-bit system registers

• RISC type instruction set

 Instruction length: 16-bit fixed length for improved code efficiency

 Load/store architecture

 Delayed branch instruction

 Instruction set based on C language

• Instruction execution time: One instruction/cycle for basic instructions

• Logical address space: 4 Gbytes

• Space identifier ASID: 8 bits, 256 logical address spaces

• Five-stage pipeline

DSP operating unit

• Mixture of 16-bit and 32-bit instructions

• 32-/40-bit internal data bus

• Multiplier, ALU, barrel shifter, and DSP register

• 16-bit x 16-bit → 32-bit one cycle multiplier

• Large-capacity DSP data register file

 Six 32-bit data registers

 Two 40-bit data registers

• Extended Harvard architecture for DSP data buses

 Two data buses

 One instruction bus

• Up to four parallel operations: ALU, multiply, two loads, and store

• Two address units to generating addresses for two memory access

• DSP data addressing modes: Increment, index register addition (with or without modulo addressing)

• Zero-overhead repeat loop control

• Conditional execution instructions

• User DSP mode and privileged DSP mode

Memory management unit (MMU)

• 4-Gbyte address space, 256 address spaces (8-bit ASID)

• Page unit sharing

• Supports multiple page sizes: 1 kbyte or 4 kbytes

• 128-entry, 4-way set associative TLB

• Specifies replacement way by software and supports random replacement algorithm

• Address assignment allows direct access to TLB contents

Cache memory

• 32-kbyte cache mixing instructions and data

• 512-entry, 4-way set associative, 16-byte block length

• Write-back, write-through, least recent used (LRU) replacement algorithm

• Single-stage write-back buffer (Continue...)