CMX813 查看數據表（PDF） - CML Microsystems Plc
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CMX813 Datasheet PDF : 21 Pages
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Multi-Standard Analogue Paging Decoder
CMX813
1.5 General Description
When the CMX813 detects the start of a tone, it generates an interrupt and reports which tone was
detected. At the end of the tone it will produce an interrupt and report Notone detected. The host micro
should measure and interpret the tone lengths and gap lengths according to calling code requirements.
The device is not designed for the decoding of multiple tones which are present simultaneously.
In 2-tone mode, the parameters for decoding each tone in the tone table are stored in a decoding ROM,
and any one of these tones can be selected for decoding via an 8-bit ROM address. Up to eight 8-bit ROM
addresses can be selected by the host micro for decoding. These are held in an internal address RAM
which downloads the addresses sequentially to the ROM and retrieves the tone decode parameters and
matches these with the received signal to a find tone decode. If a match is found, the CMX813 generates
an interrupt and reports the decoded tone table ROM address. The device can therefore decode any
number of single or 2-tone pager codes, formed by any combination of up to 8 different frequencies,
received in any order.
In 5/6 tone and HSC modes, the tone parameters are stored in ROM in groups of 16 tones in accordance
with the various international tonesets (CCIR/ZVEI etc.). Any one of these groups can be selected for
decoding at any time. ROM address sequencing is automatic. When any one of the 16 tones in that group
is decoded the device interrupts and reports the group and tone number of the tone (8 bits).
The input amplifier with suitable external components is used to adjust the received signal to the correct
amplitude for the decoder. All functions are controlled over a "C-BUS" serial µC interface.
1.5.1 Software Description
Address/Commands
Instructions and data are transferred, via "C-BUS", in accordance with the timing information given
in Figure 3.
Instruction and data transactions to and from the CMX813 consist of an Address/Command (A/C)
byte which may be followed by either:
(i)
a further instruction or data (1 btye) or
(ii) a status or Rx data reply (1 byte)
8-bit Write Only Registers
HEX
ADDRESS/
COMMAND
REGISTER
NAME
BIT 7
(D7)
BIT 6
(D6)
BIT 5
(D5)
BIT 4
(D4)
BIT 3
(D3)
BIT 2
(D2)
BIT 1
(D1)
BIT 0
(D0)
$01
GENERAL
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
RESET
ROM PAGE SELECT
DECODER BANDWIDTH
OPERATION MODE
$30
CONTROL
MSB
LSB
MSB
LSB
MSB
LSB
BIT 7
BIT 6
BIT 5 BIT 4 BIT 3 BIT 2
BIT 1
BIT 0
TONE
TONE ADDRESS
$31
ADDRESS
MSB
LSB
BIT 7
BIT6
BIT 5 BIT 4 BIT 3 BIT 2
BIT 1
BIT 0
© 2000 Consumer Microcircuits Limited
7
D/813/33
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