DVSR CODEC
8
MX802
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
60
00000001
01100000
Write to Control Register
+2 byte instruction to Control
Register
Read Status Register
61
62
63
64
65
66
67
68
69
01100001
01100010
01100011
01100100
01100101
01100110
01100111
01101000
01101001
+1 byte reply from Status Register
+2 bytes command – Immediate
+2 bytes Command – Buffered
+2 bytes Command – Immediate
+2 bytes Command – Buffered
+2 bytes ‘P’ + Write Data
+2 bytes ‘P’ + Read Data
+Write Data
Store ‘N’ pages. Start page ‘X’
Store ‘N’ pages. Start page ‘X’
Play ‘N’ pages. Start page ‘X’
Play ‘N’ pages. Start page ‘X’
Write Data. Start page ‘P’
Read Data. Start page ‘P’
Write Data – continue
Read Data -- Continue
+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.
Control and configuration is by writing instructions form the microcontroller to the Control Register (60 ).
H
Reporting of MX802 configurations is by reading the Status Register (61 ).
H
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
Plays Speech
The MX802 stores speech by digitally encoding the analog input signal and writing the
resulting digital data into the associated DRAM.
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
Reads Data
The MX802 writes data sent ver the C-BUS from the microcontroller to DRAM.
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.
ꢀ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
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