FX828D2 CMLMICRO [CML Microcircuits], FX828D2 Datasheet - Page 14

• Manufacturer Part Number: FX828D2
• Description: CTCSS/DCS/SELCALL Processor
• Manufacturer: CMLMICRO [CML Microcircuits]

CTCSS/DCS/SELCALL Processor
When Bit 7 in byte (1) is set to "1" the tone output is set at V
number "A" programmed. When Bit 7 is "0" the programmed tone is set on the output. Programming the
bits 0 to 12 to "0" puts the Tx into powersave and the output goes to V
by disabling the SUBAUDIO Tx and the CTCSS FAST DETECT.
RX TONE PROGRAM Register (Hex address $84)
This is a 16-bit register. Byte (1) is sent first. The two bytes are used to program the centre frequencies of
up to 15 tones in either the audio or sub-audio band that will be decoded by the receiver.
Each tone is identified by its address in bits 7, 6, 5 and 4 of byte (1). The remaining 12 bits contain the
data representing the tone frequency according to the formula below. If a tone is not required the 12 bits
should be set to zero.
Bit
The Hex address represented by bits 7, 6, 5 and 4 in byte (1) is used as the code to indicate which tone
has been decoded. This code appears in bits 3, 2, 1 and 0 of the SELCALL and SUB-AUDIO STATUS
Register (Hex address $81). The 15 programmed tones use Hex addresses $0 - $E.
© 2009 CML Microsystems Plc
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
7
Bit
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
6
Example: To program 100Hz when using the recommended 4.032MHz Xtal in SUBAUDIO
Bit
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
5
Bit
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
4
(CTCSS) mode.
Thus the 12-bit code is 010111001011
N is the binary representation of the
following decimal number (n):
SUBAUDIO (CTCSS)
n = INT (948982 x f
INBAND (SELCALL)
n = INT (83036 x f
<------------------------ N ----------------------->
Byte 1
Bit
3
Bit
2
n =
N =
r =
R =
=
=
=
Bit
TONE
1
INT (948982 x 100 / 4.032 x 10^6)
INT (23.536) = 23
010111 (binary)
((237245 / 4.032 x 10^6) - (23 / (4 x 100))) x 8400
11.26 (round up if exactly halfway)
11
001011 (binary)
TONE
/ f
/ f
XTAL
Bit
0
XTAL
)
)
Bit
7
14
Bit
6
R is the nearest 6-bit binary
representation of (r), where:
SUBAUDIO (CTCSS)
r = ((237245/f
INBAND (SELCALL)
r = ((20759/f
<----------------------- R ------------------------>
Bit
BIAS
5
or NOTONE without regard to the
BIAS
Bit
4
Byte 2
XTAL
. Powersave is also achieved
XTAL
) - (n/(4 x f
Bit
) - (n/(4 x f
3
Bit
2
TONE
TONE
))) x 96000
))) x 8400
Bit
1
D/828/4
FX828
Bit
0