sx150x_89b-datasheet

ADVANCED COMMUNICATIONS & SENSING
Rev 4 – 26
th
April 2011 19 www.semtech.com
SX1508B/SX1509B
World’s Lowest Voltage Level Shifting GPIO
with LED Driver and Keypad Engine
IOLED(X) level
On intensity(max)
Off intensity(min)
RegData(X)
Fade in rate determined by
register RegTRiseX
Minimum intensity duration
determined by register
RegData(x)
Fade out rate determined
by register RegTFallX
Figure 16 – LED Driver Single Shot Mode
4.8.4 Blink Mode
Invoked when TOnX != 0 and TOffX != 0.
If the I/O doesn’t support fading the LED intensity will step directly to the IOnX/IOffX value.
Off intensity(min)
RegData(X)
IOLED(X) level
Fade in rate determined by
register RegTRiseX
Minimum intensity duration
determined by register
RegTOffX
Maximum intensity
duration determined by
register RegTOnX
Fade out rate determined
by register RegTFallX
When RegData(X) is cleared, the LED
will complete any current ramp, and then
stay at minimum intensity
On intensity(max)
Figure 17 – LED Driver Blink Mode
4.8.5 LED Driver Modes
For each IO bank, the LED driver mode of fading capable IOs can be selected between linear or logarithmic in
RegMisc.
Lin. Log. Lin. Log. Lin. Log. Lin. Log. Lin. Log. Lin. Log. Lin. Log. Lin. Log.
0 0 32 4 64 13 96 28 128 53 160 88 192 135 224 198
1 0 33 4 65 13 97 28 129 53 161 88 193 135 225 198
2 0 34 4 66 13 98 30 130 53 162 88 194 135 226 198
3 0 35 4 67 13 99 30 131 53 163 88 195 135 227 198
4 0 36 5 68 14 100 31 132 56 164 93 196 142 228 207
5 0 37 5 69 14 101 31 133 56 165 93 197 142 229 207
6 0 38 5 70 14 102 32 134 56 166 93 198 142 230 207
7 0 39 5 71 14 103 32 135 56 167 93 199 142 231 207
8 1 40 6 72 16 104 34 136 60 168 98 200 150 232 216
9 1 41 6 73 16 105 34 137 60 169 98 201 150 233 216
10 1 42 6 74 17 106 35 138 60 170 98 202 150 234 216
11 1 43 6 75 17 107 35 139 60 171 98 203 150 235 216
12 1 44 7 76 18 108 36 140 65 172 104 204 157 236 225