DVSR CODEC

8

MX802

1998 MX-COM, Inc.

www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054

Doc. # 20480033.008

4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA

All trademarks and service marks are held by their respective companies.

4.1

Controlling Protocol

Control of the functions of the MX802 DVSR Codec is by a group of Address/Commands (A/Cs) and

appended instructions of data to and from the system microcontroller (See Figure 4). The use and content of

these instructions is detailed in the following pages.

Command Assignment

Address/Command (A/C) byte

Data Bytes

Hex

Binary

MSB

LSB

General Reset

01

00000001

Write to Control Register

60

01100000

+2 byte instruction to Control

Register

Read Status Register

61

01100001

+1 byte reply from Status Register

Store ‘N’ pages. Start page ‘X’

62

01100010

+2 bytes command – Immediate

Store ‘N’ pages. Start page ‘X’

63

01100011

+2 bytes Command – Buffered

Play ‘N’ pages. Start page ‘X’

64

01100100

+2 bytes Command – Immediate

Play ‘N’ pages. Start page ‘X’

65

01100101

+2 bytes Command – Buffered

Write Data. Start page ‘P’

66

01100110

+2 bytes ‘P’ + Write Data

Read Data. Start page ‘P’

67

01100111

+2 bytes ‘P’ + Read Data

Write Data – continue

68

01101000

+Write Data

Read Data -- Continue

69

01101001

+Read Data

Table 3: C-BUS Address/Commands

4.1.1

Address/Commands

Instruction and data transactions to and from this device consist of an Address/Command (A/C) byte followed

by further instruction/data reply.

4.1.2

Operation with DRAM

The MX802 can operate with up to 4Mbits of Dynamic Ram (DRAM). When used with DRAM, the MX802

performs four main functions under the control of the commands received over the C-BUS interface from the

microcontroller:

Stores Speech

The MX802 stores speech by digitally encoding the analog input signal and writing the

resulting digital data into the associated DRAM.

Plays Speech

The MX802 plays back stored speech by reading the digital data stored in the DRAM and

decoding it to provide and analog output signal.

Writes Data

The MX802 writes data sent ver the C-BUS from the microcontroller to DRAM.

Reads Data

The MX802 reads data from DRAM, sending it to the microcontroller over the C-BUS.

Data is directed to and from DRAM by the on-chip DRAM Controller.