sx150x_89b-datasheet

ADVANCED COMMUNICATIONS & SENSING
Rev 4 – 26
th
April 2011 17 www.semtech.com
SX1508B/SX1509B
World’s Lowest Voltage Level Shifting GPIO
with LED Driver and Keypad Engine
 RegInterruptMask =“XXXXXX0X”
2. We set edge sense for I/O[1] in RegSense
 RegSenseLow =“XXXX01XX”
Please note that independently from the “user defined” process described above the keypad engine, when
enabled, also uses NINT to indicate a key press.
Hence we have NINT = “user defined condition occurred” OR “keypad engine condition occurred”.
4.7 Clock Management
A main oscillator clock fOSC is needed by the LED driver, keypad engine and debounce features.
Clock management block is illustrated in figure below.
OSCIO
Clock
Mgmt
Internal
Oscillator
External
Clock
fOSC
Div
Figure 13 – Clock Management Overview
The block is configured in register RegClock (Cf §5 for more detailed information):
 Selection of internal clock source: none (OFF) or internal oscillator or external clock input from OSCIN.
 Definition of OSCIO pin function (OSCIN or OSCOUT)
 OSCOUT frequency setting (sub-multiple of fOSC)
Please note that if needed the OSCOUT feature can be used as an additional GPO (Cf. RegClock)
4.8 LED Driver
4.8.1 Overview
Every IO has its own independent LED driver (Cf §6.2 for typical LED connection) , all IOs can perform intensity
control (PWM) while some of them additionally include blinking and breathing features (Cf pin description §1)
The LED drivers of all I/Os share the same clock ClkX configurable in RegMisc[6:4]. Please note that for power
consumption reasons ClkX is OFF by default.
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:
• 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)