SX1508EVK Semtech, SX1508EVK Datasheet - Page 19

• Manufacturer Part Number: SX1508EVK
• Description: Evaluation Board For SX1508
• Manufacturer: Semtech

ADVANCED COMMUNICATIONS & SENSING
Assuming ClkX is not OFF, LED driver for IO[X] is enabled when RegLEDDriverEnable[X] = 1 in which case it
can operate in one of the three modes below:
Each IO[X] has its own set of programmable registers (Cf §5 for more detailed information):
Please note that the LED driver mode is selectable for each IO bank between linear and logarithmic. (Cf §4.9.5)
All the figures assume normal IO polarity, for inverse polarity RegData control must be inverted (does not invert
the polarity of the IO signal itself).
4.9.2
Only mode available for non blinking capable IOs (with Off intensity = 0), else invoked when TOnX = 0.
If the I/O doesn’t support fading the LED intensity will step directly to the IOnX/IOffX value.
Rev 1 – 30
RegData(X)
IOLED(X) level
Static mode (all I/Os, with or without fade in/out)
Single shot mode (blinking capable I/Os only, with or without fade in/out)
Blink mode (blinking capable I/Os only, with or without fade in/out)
RegTOnX (blinking capable I/Os only): TOnX, ON time of IO[X]
RegIOnX (all I/Os): IOnX, ON intensity of IO[X]
RegOffX (blinking capable I/Os only): TOffX and IOffX, OFF time and intensity of IO[X]
RegTRiseX(breathing capable I/Os only): TRiseX, fade in time of IO[X]
RegTFallX(breathing capable I/Os only): TFallX, fade out time of IO[X]
Static Mode
100%
RegData[X]
IO[X] Intensity (PWM value)
IOnX
IOffX
0
th
1
0
Fade In
Oct. 2009
Off intensity(min) determined by
On intensity(max) determined by
TRiseX
register RegIOffX
register RegIOnX
ON
TOnX
Figure 16 – LED Driver Static Mode
Figure 15 – LED Driver Overview
Fade in rate determined by
register RegTRiseX
Fade Out
TFallX
19
World’s Lowest Voltage Level Shifting GPIO
Fade out rate determined
by register RegTFallX
OFF
TOffX
with LED Driver and Keypad Engine
SX1507/SX1508/SX1509
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