1EDI2004AS Просмотр технического описания (PDF) - Infineon Technologies
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1EDI2004AS Datasheet PDF : 138 Pages
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EiceDRIVERTM SIL
1EDI2004AS
Functional Description
SCLK
Master SDO
SDI
NCS
SCLK
SDI Slave 1
SDO
NCS
SCLK
SDI Slave 2
SDO
NCS
Figure 7 SPI Daisy Chain Bus Topology
SCLK
SDI Slave n
SDO
NCS
Physical Layer
The SPI interface relies on two shift registers:
• A shift output register, reacting on the rising edges of SCLK.
• A shift input register, reacting on the falling edges of SCLK.
When signal NCS is inactive, the signals at pins SCLK and SDI are ignored. The output SDO is in tristate.
When NCS is activated, the shift output register is updated internally with the value requested by the previous
SPI access.
At each rising edge of the SCLK signal (while NCS is active), the shift output register is serially shifted out by
one bit on the SDO pin (MSB first). At each falling edge of the clock pulse, the data bit available at the input SDI
is latched and serially shifted into the shift input register.
At the deactivation of NCS, the SPI logic checks how many rising and falling edges of the SCLK signal have been
received. In case both counts differ and / or are not a multiple of 16, an SPI Error is generated. The SPI block
then checks the validity of the received 16-bit word. In case of a non valid data, an SPI error is generated. In
case no error is detected, the data is decoded by the internal logic.
The NCS signal is active low.
Input Debouncing Filters
The input stages of signals SDI, SCLK, and NCS include each a Debouncing Filter. The input signals are that way
filtered from glitches and noise.
The input signals SDI and SCLK are analyzed at each edge of the internal clock derived from OSC1. If the same
external signal value is sampled three times consecutively, the signal is considered as valid and is processed
by the SPI logic. Otherwise, the transition is considered as a glitch and is discarded.
Data Sheet
23
Rev. 2.0
2019-01-16
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