CMX138 CML Microcircuits, CMX138 Datasheet - Page 38

• Manufacturer Part Number: CMX138
• Description: Audio Scrambler and Sub-Audio Signalling Processor
• Manufacturer: CML Microcircuits

Audio Scrambler and Sub-Audio Signalling Processor
The detailed descriptions of the C-BUS registers are presented in numerical order and should be read in
conjunction with the relevant functional descriptions.
9.1.1
A reset is automatically performed when power is applied to the CMX138. A reset can be issued as a C-
BUS command, either as a General Reset command ($01), or by setting the appropriate bit (b5) in the
Powerdown Control register ($C0). In the latter case, an option exists to protect the values held in the
Program Block (which is accessed via the Programming register, $C8). The action of each reset type is
shown in the table below:
Following a Reset operation, the internal checksum values are made available in the $A9, $AA, $B8 and
$B9 registers. The device ID is available in $C5.
The status of the Power Down register, $C0, can be read back in $C4 to ensure that C-BUS
communications are operational.
9.1.2
The General Reset command has no data attached to it. It puts the device registers into the states listed
below. A power-on reset performs the same action.
© 2008 CML Microsystems Plc
Reset Operations
General Reset - $01 write
1 Power on
2
3
4
Reset type
General Reset
(C-BUS $01)
Reset
(C-BUS $C0 b5)
Reset
(C-BUS $C0 b5)
Table 7 Reset Operations
Page 38
Protect bit
($C0 b4) state
cleared by h/w
cleared by h/w
0
1
Program
Block state
default
default
default
protected
D/138_FI1.0/5
CMX138