sx1508bevk Semtech Corporation, sx1508bevk Datasheet - Page 15

• Manufacturer Part Number: sx1508bevk
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
When successive register data (WD1...WDn) is supplied by the master, the register address can be
automatically incremented or kept fixed depending on the setting programmed in RegMisc.
4.5.2
After the start condition [S], the slave address (SA) is sent, followed by an eighth bit (‘0’) indicating a Write. The
slave then Acknowledges [A] that it is being addressed, and the Master responds with an 8 bit Data consisting of
the Register Address (RA). The slave Acknowledges [A] and the master sends the Repeated Start Condition
[Sr]. Once again, the slave address (SA) is sent, followed by an eighth bit (‘1’) indicating a Read.
The slave responds with an Acknowledge [A] and the read Data byte (RD0). If the master needs to read more
data it will acknowledge [A] and the slave will send the next read byte (RD1). This sequence can be repeated
until the master terminates with a NACK [N] followed by a stop [P].
When successive register data (RD1...RDn) is read by the master, the register address will be automatically
incremented or kept fixed depending on the setting programmed in RegMisc.
4.6
4.6.1
Each input can be individually debounced by setting corresponding bits in RegDebounce register. At power up
the debounce function is disabled. After enabling the debouncer, the change of the input value is accepted only if
the input value is identical at two consecutive sampling times.
The debounce time common to all IOs can be set in RegDebounceConfig register from 0.5 to 64ms (fOSC =
2MHz).
4.6.2
SX1508B, and SX1509B integrate a fully programmable keypad scanning engine to implement keypad
applications up to 8x8 matrix (i.e. 64 keys).
Please note that SX1509B also implements an Auto Sleep/Wakeup feature to save power consumption when no
key has been pressed for a programmed time.
Rev 3 – 9
I/O Banks
Input Debouncer
Keypad Scanning Engine
READ
th
Sept. 2010
Figure 11 - 2-Wire Serial Interface, Read Operation
Figure 10 – Example: Write RegData Register
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1
World’s Lowest Voltage Level Shifting GPIO
SX1507B/SX1508B/SX1509B
with LED Driver and Keypad Engine
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