SA3229 Datasheet, PDF (10/16 Pages) ON Semiconductor – Preconfigured DSP System

RHYTHM SA3229
In the following mode descriptions, it is assumed that the
PullUpDown setting has been properly configured for the
MS switch wiring so that a CLOSED switch state is at the
correct input logic level.
Mode 1: Momentary Switch on MS1
This mode uses a single momentary switch on MS1 input
to change memories. Using this mode causes the part to start
in memory A, and whenever the button is pressed, the next
valid memory is loaded. When the user is in the last valid
memory, a button press causes memory A to be loaded.
Thus, the possible selection sequences are:
If 4 valid memories: ABCDABCDA…
If 3 valid memories: ABCABCA…
If 2 valid memories: ABABA…
If 1 valid memory: AAA…
Mode 2: Momentary Switch on MS1, Static Switch on
MS2
(D−only, Jump to Last Memory)
This mode uses a static switch on MS2 and a momentary
switch on MS1 to change memories. It can be used to support
the Automatic Telecoil feature, see section Automatic
Telecoil.
If the static switch on MS2 is OPEN, the part starts in
memory A and is controlled by the momentary switch on
MS1 as described in section Momentary Switch on MS1,
with the exception that memory D is not used. If the static
switch on MS2 is set to CLOSED, the part automatically
jumps to memory D (occurs on startup or during normal
operation). In this setup, the state of the momentary switch
on MS1 is ignored. When MS2 is set to OPEN, the part loads
in the memory that was active prior to jumping to memory
D.
The possible memory selection sequences are:
If MS2 = OPEN and there are four valid memories, MS1
selects: ABCABCA…
If MS2 = OPEN and there are three valid memories, MS1
selects: ABABA…
If MS2 = OPEN and there is one valid memory: A
If MS2 = CLOSED: D
Mode 3: Static Switch on MS1 and MS2
This mode uses two static switches to change memories.
In this mode, it is possible to jump from any memory to any
other memory by changing the state of both switches. If the
two switches are changed one after 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 6. STATIC SWITCH TRUTH TABLE:
D−ONLY DISABLED
Binary State (MS1/MS2)
Selected Memory
OPEN OPEN
Memory A
CLOSED OPEN
Memory B
OPEN CLOSED
Memory C
CLOSED CLOSED
Memory D
Mode 4: Static Switch on MS1, Static Switch on MS2
(D−only, Jump to Last Memory)
This mode uses two static switches to change memories.
Similar to the behaviour described in the Static Switch on
MS1 and MS2 section, this mode will switch to memory D
if the static switch on MS2 is CLOSED (the state of the
switch on MS1 is ignored). The mode, however, supports a
maximum of three memories (even if four valid memories
are programmed). This mode can be used to support the
Automatic Telecoil feature (see the Automatic Telecoil
section).
In this mode, it is possible to jump from any memory to
any other memory by changing the state of both switches. If
the two switches are changed one after 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 7. STATIC SWITCH TRUTH TABLE:
D−ONLY ENABLED; (EXAMPLE WITH THREE VALID
MEMORIES)
Binary State (MS1/MS2)
Selected Memory
OPEN OPEN
Memory A
CLOSED OPEN
Memory B
X CLOSED
Memory D
Rocker Switch Support
The device supports connection of a rocker switch to the
digital volume control interface that can perform volume
control (VC) adjustments and/or memory selection (MS).
There are three modes of operation:
• Digital Volume Control Mode
• Momentary Memory Select Mode
• Mixed Mode (VC and MS)
In Digital VC mode, the rocker switch provides the digital
volume control functionality as described in this section.
www.onsemi.com
10