sx1508bevk Semtech Corporation, sx1508bevk Datasheet - Page 18

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sx1508bevk

Manufacturer Part Number
sx1508bevk
Description
Manufacturer
Semtech Corporation
Datasheet
ADVANCED COMMUNICATIONS & SENSING
When NINT is low (i.e. interrupt occurred), it can be reset back high (i.e. cleared) by writing 0xFF in
RegInterruptSource (this will also clear corresponding bits in RegEventStatus register).
The interrupt can also be cleared automatically when reading RegData register (Cf. RegMisc)
Example: We want to detect rising edge of I/O[1] on SX1508B (NINT will go low).
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”.
4.8
A main oscillator clock fOSC is needed by the LED driver, keypad engine and debounce features.
Clock management block is illustrated in figure below.
The block is configured in register RegClock (Cf §5 for more detailed information):
Please note that if needed the OSCOUT feature can be used as an additional GPO (Cf. RegClock)
4.9
4.9.1
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:
Rev 3 – 9
1. We enable interrupt on I/O[1] in RegInterruptMask
2. We set edge sense for I/O[1] in RegSense
Clock Management
LED Driver
RegInterruptMask =“XXXXXX0X”
RegSenseLow =“XXXX01XX”
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)
Overview
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)
th
Sept. 2010
Figure 15 – Clock Management Overview
Oscillator
External
Internal
Clock
OSCIO
Clock
Mgmt
18
Div
World’s Lowest Voltage Level Shifting GPIO
fOSC
SX1507B/SX1508B/SX1509B
with LED Driver and Keypad Engine
www.semtech.com

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