SA3286 Datasheet, PDF (12/16 Pages) ON Semiconductor – Pre-configured DSP System

INSPIRIA SA3286
Memory Select Switches
One or two, two−pole Memory Select (MS) switches can
be used with the Inspiria SA3286. This enables users
tremendous flexibility in switching between configurations.
These switches may be either momentary or static and are
configurable to be either pull−up or pull−down through the
settings tab in IDS.
Up to four memories can be configured on the Inspiria
SA3286. Memory A must always be valid. All memory
select options are selectable via the settings tab in IDS.
Momentary Switch on MS
This mode uses a single momentary switch on MS (Pin4)
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.
This mode is set by programming the ‘MSSMode’
parameter to ‘Momentary’ and ‘Donly’ to ‘disabled’.
Example:
If 4 valid memories: ABCDABCDA…
If 3 valid memories: ABCABCA…
If 2 valid memories: ABABA…
If 1 valid memories: AAA…
Momentary Switch on MS, Static Switch on MS2 (Jump
to Last Memory)
This mode uses a static switch on MS2 (Pin5) and a
momentary switch on MS (Pin4) to change memories. If the
static switch is OPEN, the part starts in memory A and
behaves like momentary, with the exception that memory D
is not used. If the static switch on MS2 is set to HIGH, the
part automatically jumps to memory D (occurs on start−up
or during normal operation). In this setup, the momentary
switch’s state is ignored, preventing memory select beeps
from occurring. When MS2 is set to OPEN, the part loads in
the last select memory.
This mode is set by programming the ‘MSSMode’
parameter to ‘Momentary’ and ‘Donly’ to ‘enabled’.
Example:
If MS2 = OPEN and there are 4 valid memories:
ABCABCA…
If MS2 = OPEN and there are 3 valid memories: ABABA…
If MS2 = HIGH: D…
Table 3. DYNAMIC EXAMPLE WITH FOUR VALID MEMORIES (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
C
D
D
D
C
A
B
D
B
C
A
B
C
A
Static Switch on MS and MS2
This mode uses two static switches to change memories.
Table 4 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.
This mode is set by programming the ‘MSSMode’
parameter to ‘static’ and ‘Donly’ to ‘disabled’.
Table 4. MEMORY SELECTED IN STATIC SWITCH ON
MS and MS2 MODE; Internal Resistors Set to Pull Down
MS
MS2
Memory
OPEN OPEN
A
HIGH OPEN
B (if valid, otherwise A)
OPEN HIGH
C (if valid, otherwise A)
HIGH
HIGH
D (if valid, otherwise A)
Static Switch on MS, Static Switch on MS2 (Jump to
Last Memory)
This mode uses two static switches to change memories.
Unlike in the previous example, this mode will switch to the
last valid memory when the static switch on MS2 is HIGH.
This means that this mode will only use a maximum of three
memories (even if four valid memories are programmed).
Table 5 describes which memory is selected depending on
the state of the switches.
This mode is set by programming the ‘MSSMode’
parameter to ‘static’ and ‘Donly’ to ‘enabled’.
Table 5. MEMORY SELECTED IN STATIC SWITCH ON
MS, Static Switch on MS2 (Jump to Last Memory)
Mode; Internal Resistors Set to Pull Down
MS
MS2
Memory
OPEN OPEN
A
HIGH OPEN
B (if valid, otherwise A)
OPEN
HIGH
D
HIGH
HIGH
D
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