A1190 ALLEGRO [Allegro MicroSystems], A1190 Datasheet - Page 11

• Manufacturer Part Number: A1190
• Description: Programmable, Chopper-Stabilized, Two Wire Hall-Effect Switches
• Manufacturer: ALLEGRO [Allegro MicroSystems]

A1190, A1192,
and A1193
Try Mode In Try mode, bit field addressing is accomplished by
applying a series of V
shown in figure 6. Each pulse increases the bit field value for the
selected parameter, increasing by one on the falling edge of each
additional V
the quantity of V
called the code. Addressing activates the corresponding fuse
locations in the given bit field by increasing the binary value of
an internal DAC, up to the maximum possible code. As the value
of the bit field code increases, the value of the programmable
parameter changes. Measurements can be taken after each V
pulse to determine if the required result for the programmable
parameter has been reached. Cycling the supply voltage resets
all the locations in the bit field that have un-blown fuses to their
initial states.
When setting the B
values can be traversed from low to high, or from high to low. To
accommodate this direction selection, the value of the bit field
(and code) defaults to the value 1, on the falling edge of the final
register selection V
provided in figure 11.
Figure 5. Register selection pulse sequence
Figure 6. Try mode bit field addressing pulses
PM
V
V
V
PM
PH
PL
0
V
V
V
pulse. When addressing the bit field in Try mode,
PM
PH
PL
PM
0
OP
PH
pulses is represented by a decimal number
PM
Trim parameter, as an aid to programming,
pulse (see figure 5). A complete example is
pulses to the VCC pin of the device, as
Key
PM
Programmable, Chopper-Stabilized,
Blow Mode After the required code is determined for a given
parameter, its value can be set permanently by blowing individual
fuses in the appropriate register bit field. Blowing is accom-
plished by selecting the register, then the Blow mode selection
key, followed by the appropriate bit field address, and ending
the sequence with the Blow pulse. The Blow mode selection key
is a sequence of nine V
complete example is provided in figure 12.
The Blow pulse consists of a V
t
internal to the device. Due to power requirements, the fuse for
each bit in the bit field must be blown individually. The A119x
family built-in circuitry allows only one fuse at a time to be
blown. During Blow mode, the bit field can be considered a “one-
hot” shift register. Table 3 relates the quantity of V
the binary and decimal values for Blow mode bit field address-
ing. It should be noted that the simple relationship between the
quantity of V
where n is the quantity of V
state of decimal code 0 (binary 000000).
Figure 7. Example of code 5 broken into its binary components
BLOW
Table 3. Blow Mode Bit Field Addressing
Two Wire Hall-Effect Switches
, to permanently set an addressed bit by blowing a fuse
V
Quantity of
PM
Pulses
1
2
3
4
5
6
PM
Address Code Format
Address Code Format
pulses and the corresponding code is:
Bit Field Selection
Code in Binary
Fuse Blowing
Fuse Blowing
Target Bits
PM
Binary Register
pulses followed by one V
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Worcester, Massachusetts 01615-0036 U.S.A.
2
PM
n
000001
000010
000100
001000
010000
100000
Setting
= Code,
PH
pulses. The bit field has an initial
Code 4
(Decimal Equivalents)
pulse of sufficient duration,
(Decimal Equivalent)
Bit 2
(Binary)
1 0 1
Code 5
Code 1
Bit 0
Equivalent Code
PM
PH
16
32
1
2
4
8
pulses to
pulse. A
11