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FX802J View Datasheet(PDF) - CML Microsystems Plc

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Description
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FX802J
CML
CML Microsystems Plc CML
FX802J Datasheet PDF : 14 Pages
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Controlling Protocol
Control of the functions of the FX802 DVSR Codec is by a group of Address/Commands (A/Cs) and appended instructions or
data to and from the system µController (see Figure 5). The use and content of these instructions is detailed in the following
paragraphs and tables.
Command
Assignment
Address/Command (A/C) Byte
+
Hex.
Binary
MSB
LSB
General Reset
01
Write to Control Register
60
Read Status Register
61
Store ‘N’ pages. Start page ‘X’
62
Store ‘N’ pages. Start page ‘X’
63
Play ‘N’ pages. Start page ‘X’
64
Play ‘N’ pages. Start page ‘X’
65
Write Data. Start page ‘P’
66
Read Data. Start page ‘P’
67
Write Data – Continue
68
Read Data – Continue
69
00000001
01100000 +
01100001 +
01100010 +
01100011 +
01100100 +
01100101 +
01100110 +
01100111 +
01101000 +
01101001 +
Table 1 “C-BUS” Address/Commands
Data
Byte/s
2 byte Instruction to Control Register
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
Read data
Address/Commands
Instruction and data transactions to and from this device
consist of an Address/Command (A/C) byte followed by
either:
(i) a further instruction or data, or
(ii) a Status or data Reply.
Control and configuration is by writing instructions from the
µController to the Control Register (60H).
Reporting of FX802 configurations is by reading the Status
Register (61 ). Instructions and data are transferred, via
H
“C-BUS,” in accordance with the timing information given in
Figures 5 and 6.
A complete list of DBS 800 “C-BUS” Address locations is
published in the System Support Document.
Speech
The delta encoder and decoder sampling rates are
independently set, via the Control Register (Table 4), to
(nominally) 16, 25, 32, 50 or 64kbits/s (see Tables 2 and 3),
allowing the user to choose between speech-quality and
storage-time, whilst providing for time-compression or
expansion of the speech signals.
The DVSR Codec can handle from 256kbits to 4Mbits of
DRAM, giving, in the case of 32kbit/s sampling rate, from 8
to 131 seconds of speech storage.
For speech storage purposes, the memory is divided into
'pages' of 1024 bits each, corresponding to 32ms at a
32kbit/s sampling rate.
A 256kbit DRAM contains
A 1Mbit DRAM contains
4Mbit of DRAM contains
256 pages.
1024 pages.
4096 pages.
The Delta Codec may be used without DRAM, when the
decoder sampling rate (8 to 64 kbits/s) is determined by an
external clock source applied to the Decoder Clock pin.
Operation with DRAM
The FX802 can operate with up to 4Mbits of DRAM. When
used with DRAM the DVSR Codec performs four main
functions under the control of commands received over the
“C-BUS” interface from the µController:
Stores Speech by digitally encoding the analogue input
signal and writing the resulting digital data into the
associated Dynamic RAM (DRAM).
Plays stored speech by reading the digital data stored in the
DRAM and decoding it to provide an analogue output
signal.
Writes data sent over the “C-BUS” from the µController to
DRAM.
Reads data from DRAM, sending it to the µC over the
“C-BUS”.
‘Data’ is directed to and from DRAM by the on-chip DRAM
Controller.
Store and Play Speech Commands
Speech storage and playback may take place
simultaneously.
These commands are transmitted, via “C-BUS,” to the
FX802, in the form:
STORE or PLAY ‘N’ (1024-bit) pages (of encoded
speech data) starting at page ‘X.’
‘N’ is any number from 1 to 16 (pages) and ‘X’ from (page) 0
to 4095 (4Mbit DRAM), as illustrated below.
Preceded by the A/C, this command writes 16-bits (byte 1
(first) and byte 0) of data from the µC to the FX802 Store or
Play Command Buffer.
MSB
Byte 1
Byte 0
LSB
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
‘N’
‘X’
5
 

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