Programmable Paging Tone Decoder
CMX823
Fast and Slow measurement modes are selectable via the CONTROL Register. The Fast mode is
intended for 5/6-tone pager tonesets, which require a faster response and the Slow mode is intended for
2-tone pager tonesets, where slower response times are acceptable.
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 the 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 4.
Instruction and data transactions to and from the CMX823 consist of an Address/Command (A/C)
byte that may be followed by either:
(i)
(ii)
8-bit Write Only Registers
HEX
ADDRESS/
COMMAND
$01
REGISTER
NAME
GENERAL
RESET
BIT 7
(D7)
N/A
RAM
SELECT
$30
$32
CONTROL
BIT 7
AUXILIARY
CONTROL
BIT 7
1 TONE
DECODE
$33
GENERAL
BIT 7
BIT6
BIT 5
ST
a further instruction or data bytes or
a status byte or Rx data reply bytes
BIT 6
(D6)
N/A
FAST/
SLOW
SELECT
BIT 6
BIT 5
(D5)
N/A
BIT 4
(D4)
N/A
BIT 3
(D3)
N/A
BIT 2
(D2)
N/A
BIT 1
(D1)
N/A
BIT 0
(D0)
N/A
DECODER BANDWIDTH
OPERATION MODE
MSB
BIT 5
BIT 4
BIT 3
LSB
BIT 2
MSB
BIT 1
LSB
BIT 0
I/P
SIGNAL
FLOW
Reserved
BIT 1
2 TONE
DECODE
ND
BIT 0
Reserved
MSB
BIT 4
BIT 3
Not used
BIT 2
BIT 1
LSB
BIT 0
©
2003 CML Microsystems Plc
8
D/823/3
CMLMICRO [ CML MICROCIRCUITS ]
