GMSK Packet Data Modem and RF Transceiver
CMX990
Special Command (SPC)
$1A
Write
7
6
5
4
3
2
1
0
Bit:
Special Command
The 8 bit value written to this register instructs the modem to perform special tasks such as loading
coefficients or reading receive values. When executing a special task that requires input data, the data
should be loaded into the Special Data0/1 registers before writing the special command. When the
special command has completed the 'SPC command complete' bit will be set to '1' and the host can read
out any reply data from the Special Data0/1 registers. Note: When the internal circuits read this register
as a non zero value they will attempt to complete the task when there is a gap in processing.
Input Data
Data 1 Data 0
$1B $1C $1D $1E
Returned Data
Cmd
No.
Function
Notes
Data1
Data 0
(Hex)
$1B $1C
$1D $1E
Null
00
01
09
0A
-
-
-
-
-
-
-
-
-
-
-
-
-
No command - do nothing
address1 = address
Set address
Set tx filter
address
-
-
address1 = tx filter address
Set rx channel
filter
address1 = rx channel filter
address
Set rx gauss
0B
-
-
-
-
address1 = rx gauss filter
address
Poke(addr)
Peek(addr)
Branch
0C
0D
0E
11
data
address
address
address
-
-
-
-
-
-
*address=data
-
-
-
*address
-
-
Branches to address
Enter setup
Enters setup (debug code
only)
Enter setup
and wait
12
-
-
-
-
Enters setup (debug code
only) synced to sample clk
Exit setup
13
14
-
-
-
-
-
-
-
-
Returns to tx/rx
Exit setup and
initialise
Returns to tx/rx & initialises
User channel
filter
15
-
-
-
-
-
-
-
-
-
-
-
Loads rx channel filter from
data at address1
Set BT = 0.3
1A
Tx and Rx with BT = 0.3
(Default setting)
Tx and Rx with BT = 0.5
Set BT = 0.5
Set AFC limit
1B
1C
18
-
Limit
Offset
Set Decode
Threshold
-
-
-
Set data decode threshold
level. Default = 2400
Notes: *address = data in memory pointed to by 'address'.
ã 2004 CML Microsystems Plc
51
D/990/1
CMLMICRO [ CML MICROCIRCUITS ]
