GA3227 Datasheet, PDF (9/13 Pages) ON Semiconductor – Pre-configured DSP System

CONSOLIDATOR GA3227
ARKonline and set in IDS, enabling manual adjustment of
the telecoil gain compensation.
Volume Control & Trimmers
All parameters can be controlled via the SDA or assigned
to the trimmers. The four trimmers have flexible parameter
assignments so that any of them can be assigned to any
available parameters. A complete list of parameters is
available on ARKonline.
Both the external VC and trimmers are configured to work
with a three−terminal 0.1 MW – 1 MW variable resistor. The
volume control should have a log taper, while the trimmers
should have a linear taper. Hysteresis is built into the
circuitry to prevent unintentional level toggling.
Bi−Quadratic Filter
The bi−quadratic filter allows for additional frequency
shaping. The filter coefficients can be entered in IDS.
AGC−O
The AGC−O module is an output limiting circuit with a
fixed compression ratio of ∞ : 1. The limiting level is
programmable as a level measured as dB from full scale.
0 dBFS is the maximum output of the device. The AGC−O
module has its own twin level detector, with programmable
attack and release time constants.
MS and MS2 Switches
There are two, two−pole Memory Select (MS) switches
available on the Consolidator GA3227, enabling users
flexibility in switching between configurations. MS
switches can be either momentary or static, as set up in
ARKonline, and are configurable to be either pull−up or
pull−down through the setting tab in IDS. In extended
programmable mode, the switch must be set to pull−down.
MS2 is a static switch and is used to select the third memory
(Memory C).
Up to three memories can be configured in extended
programmable mode, or one memory in trimmer mode. All
memory select options are selectable via the ARKonline
wizard.
In simple trimmer mode, there is one method for memory
select. In this mode, when the telecoil is enabled, MS
switches the Consolidator GA3227’s input between the
microphone and the telecoil using either a momentary or
static switch which is selectable using ARKonline.
There are four memory select modes available in
programmable and multi−memory trimmer mode as
follows:
• Momentary Switch on MS
• Momentary Switch on MS, static switch on MS2 (jump
to Memory C)
• Static switch on MS and MS2
• Static switch on MS, static switch on MS2 (jump to
Memory C)
Momentary Switch on MS
This mode uses a single momentary switch on MS to
change memories. Using this mode causes the part to toggle
among memories A, B and C.
Momentary Switch on MS, Static Switch on MS2 (Jump
to Memory C)
This mode uses a static switch on MS2 and a momentary
switch on MS to change memories. If the static switch is
OPEN, the part starts in memory A and toggles between
memory A and B. If the static switch on MS2 is set to HIGH,
the part automatically jumps to the memory C (occurs on
startup or during normal operation). In this setup, the
momentary switch’s state is ignored. This prevents memory
select beeps from occurring. When MS2 is set to OPEN, the
part loads in the last select memory.
Table 4. DYNAMIC EXAMPLE WITH 3 VALID MEMORIES
(Conditions: T = momentary switch is toggled; 0 = OPEN; 1 = HIGH)
MS2
0
0
0
1
1
1
0
0
0
1
0
0
0
0
0
0
MS
0
T
T
0
T
T
0
T
T
0
0
T
T
T
T
T
Memory A
B
A
C
C
C
A
B
A
C
A
B
A
B
A
B
Static Switch on MS and MS2
This mode uses two static switches to change memories.
Table 5 describes which memory is selected depending on
the state of the switches.
In this mode, it is possible to jump from any memory to
any other memory simply by changing the state of both
switches. If both switches are changed simultaneously, then
the transition is smooth. Otherwise, if one switch is changed
and then the other, the part transitions to an intermediate
memory before reaching the final memory.
The part starts in whatever memory the switches are
selecting. If a memory is invalid the part defaults to
memory A.
Table 5. SWITCH FOR MS and MS2
MS
MS2
Memory
OPEN OPEN
A
HIGH OPEN
B (if valid, otherwise A)
OPEN
HIGH
A
HIGH
HIGH
C (if valid, otherwise A)
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