LM3559TLX National Semiconductor Corporation, LM3559TLX Datasheet - Page 16

• Manufacturer Part Number: LM3559TLX
• Description: Synchronous Boost Flash Driver With Dual 900 Ma High Side Current Sources 1.8a Total Flash Current
• Manufacturer: National Semiconductor Corporation

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HARDWARE TORCH
With Configuration Register 1 Bit [7] = 1, TX1/TORCH is con-
figured as a hardware Torch mode enable. In this mode
(TORCH mode), a high at TX1/TORCH turns on the LED cur-
rent at the programmed Torch current setting. The STROBE
input and I
mode. In hardware torch mode, both LED1 and LED2 current
sources will turn off after a flash event and Configuration
Register 1 Bit [7] will be reset to 0. In this situation, to re-enter
torch mode via hardware torch, the hardware torch enable bit
(Configuration Register 1 Bit [7]) must be reset to 1.
5
GPIO1 MODE
With Bit [0] of the GPIO Register set to 1, the TX1/TORCH/
GPIO1 pin is configured as a logic I/O. In this mode the TX1/
TORCH/GPIO1 pin is readable and writable as a logic input/
output via bits [2:1] of the GPIO Register. See
details the functionality of the TX1/TORCH/GPIO1 input.
2
C Enabled flash takes precedence over TORCH
FIGURE 4. TX1 or TX2 Interrupt Event
FIGURE 5. Hardware Torch Mode
Table
9.
Figure
16
TX2/INT/GPIO2
The TX2/INT/GPIO2 pin has a triple function. In TX2 mode
(Default) the TX2/INT/GPIO2 pin is an active high Flash in-
terrupt. With GPIO Register bit [3] = 1 the TX2/INT/GPIO2 pin
is configured as general purpose logic I/O. With GPIO Reg-
ister bit [6] = 1, and with the TX2/INT/GPIO2 pin configured
as a GPIO2 output, the TX2/INT/GPIO2 pin is an interrupt
output.
TX2 MODE
In TX2 mode, when Configuration Register 1, bit [6] = 0, the
TX2/INT/GPIO2 pin has active low polarity. Under this condi-
tion when the LM3559 is engaged in a Flash event and TX2
is pulled low, both LED1 and LED2 are forced into Torch
mode. In TX2 mode with Configuration Register 1, bit [6] = 1
the TX2/INT/GPIO2 input has active high polarity. Under this
condition when the LM3559 is engaged in a Flash event and
the TX2/INT/GPIO2 pin is driven high, both LED1 and LED2
are forced into Torch mode. During a flash interrupt event if
the TX2/INT/GPIO2 input is disengaged the LED current will
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