LM3560 Datasheet, PDF (17/42 Pages) Texas Instruments – LM3560 Synchronous Boost Flash Driver w/ Dual 1A High-Side Current Sources (2A Total Flash Current)

FIGURE 5. Hardware Torch Mode
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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 GPIO REGIS-
TER (Address 0x20) for programming the GPIO1 output.
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 (GPIO2). With
GPIO Register bit [6] = 1 and with GPIO2 set for GPIO output,
the TX2/INT/GPIO2 pin is an interrupt output
TX2 MODE
In TX2 mode, when Configuration Register 1, bit [6] = 0, TX2
is an active low flash interrupt. Under this condition when the
LM3560 is engaged in a Flash event and TX2 is pulled low,
the active current source (LED1 and/or LED2) are forced into
Torch mode. In TX2 mode with Configuration Register 1, bit
[6] = 1, TX2 is configured for active high polarity. Under this
condition, when the LM3560 is engaged in a Flash event and
TX2 is driven high, the active current source (LED1 and/or
LED2) are forced into Torch mode. During a TX2 interrupt
event, if the TX2 input is disengaged, the LED current will
return to the previous flash current level. Figure 4 details the
functionality of the TX2 Interrupt.
TX2 Shutdown
TX2 also has the capability to force shutdown. When bit [0] of
Configuration Register 2 is set to a '1', TX2 will force shutdown
when active. For example, if TX2 is configured for TX2 mode
with active high polarity, and bit [0] of Configuration Register
2 is set to '1' then when TX2 is driven high, the active current
sources (LED1 and/or LED2) will be forced into shutdown.
Once the active current sources are forced into shutdown by
activating TX2, the current sources can only be re-enabled in
flash mode if TX2 is pulled low and the Flags register is read
back. If only the Flags register is read back and TX2 is kept
high, the device will be re-enabled into torch mode and not
shutdown. This occurs because the TX2 shutdown feature is
an edge-triggered event. With active high polarity the TX2
shutdown requires a rising edge at TX2 in order to force the
current sources into shutdown. Once shut down, it takes a
readback of the flags Register and another rising edge at TX2
to force shutdown again. Figure 6 details TX2 shutdown
mode.
FIGURE 6. TX1 or TX2 (Force Shutdown) Response
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GPIO2 MODE
With Bit [3] of the GPIO Register set to 1, the TX2/INT/GPIO2
pin is configured as a logic I/O. In this mode the TX2/INT/
GPIO2 pin is readable and writable as a logic input/output via
bits [5:4] of the GPIO Register. See Table 8 for programming
the GPIO2 output.
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