VR4102 datasheet(31/701 Pages) NEC

31 / 701 page

CHAPTER 1 INTRODUCTION

1.4.1 Internal Block Structure

The following provides an outline of the peripheral units.

For the CPU core, refer to 1.5 VR4100 CPU CORE.

(1) Bus Control Unit (BCU)

In the VR4102, the bus control unit (BCU) transfers data between the VR4100 CPU core and SysAD bus. It also

controls external circuits, such as the LCD controller connected to the system bus, DRAM, ROM (flash memory

or masked ROM), and PCMCIA controller, and transfers data between the VR4102 and these external devices,

using the address and data buses.

(2) Real-time Clock Unit (RTC)

The real-time clock (RTC) is provided with an accurate counter that operates on a 32.768-kHz clock pulse

supplied from the clock generator.

It is also provided with several counters and Compare registers for

controlling various interrupts.

(3) Deadman’s Switch Unit (DSU)

The Deadman’s switch unit (DSU) is used to check whether the processor is running normally. If the register of

this unit is not cleared by software within a specified period, the system is shut down.

(4) Interrupt Control Unit (ICU)

The interrupt control unit (ICU) controls interrupt requests that are caused by factors either internal or external to

the VR4102, and informs the VR4100 CPU core when an interrupt request occurs.

(5) Power Management Unit (PMU)

The power management unit (PMU) outputs signals necessary to control the power of the entire system

including the VR4102. The signals are used to control the PLL of the VR4100 CPU core and the internal clocks

(pipeline clock, TClock, and MasterOut) in low-power modes.

(6) Direct Memory Access Address Unit (DMAAU)

The direct memory access address unit (DMAAU) controls the address of three different DMA transfers.

(7) Direct Memory Access Control Unit (DCU)

The direct memory access control unit (DCU) controls the arbitration of three different DMA transfers.

(8) Clock Mask Unit (CMU)

The clock mask unit (CMU) controls the way the clocks TClock and MasterOut are supplied from the VR4100

CPU core to internal peripheral units.

(9) General Purpose I/O Unit (GIU)

The general purpose I/O unit (GIU) controls 49 GPIO pins.

(10) Audio Interface Unit (AIU)

The audio interface unit (AIU) executes mic-input sampling and audio signal output by controlling the internal

A/D converter and D/A converter.

VR4102 Datasheet(PDF) 31 Page - NEC