
FingerTIP
Infineon Technologies
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FTF 1100 MF1 V2.0 databook 3.3 (05.00)
4.2 Pin Description of the SPI Interface
The following table (table 6) shows the SPI pin names and their corresponding pins on the
FingerTIP side.
SPI Pin Name FingerTIP Pin Name
Direction
Function
EPP/SPI
Master
→ FTIP SPI Mode: Set to VSS
/CS
DA2/CS
Master
→ FTIP Chip Select
SO
DA3/SO
FTIP
→ Master Serial Output
SI
DA0/SI
Master
→ FTIP Serial Input
SCK
DA1/SCK
Master
→ FTIP Serial Clock
Table 6: SPI Pin Names
4.2.1 EPP/SPI
When power is switched on, the EPP/SPI pin must be set to ground for selecting the SPI
mode. It is not possible to change from EPP to SPI mode without switching power off and
on. If the sensor is in SPI mode, the EPP/SPI pin must be at low level all the time.
4.2.2 Chip Select (/CS)
With the Chip Select (/CS) the FingerTIP can be selected (low active). Therefore this
input must be set to low to select the sensor. After power-on and before a command can
be sent, the sensor must be selected with a high-to-low transition on pin /CS. Otherwise no
instructions are accepted. The sensor must be selected throughout the entire command
cycle. Between two command sequences the sensor must be deselected with a high level
on the /CS input. Before the sensor is selected, the Serial Clock (SCK) must be set to low
for a minimum of tLCS (see table 7). Otherwise the sensor will not be selected.
If the sensor is deselected, the Serial Output SO is tristate. This allows more than one SPI
devices on the same bus.
4.2.3 Serial Input (SI)
The Serial Input (SI) is used to receive data from the master. The data will be accepted
with the rising edge of the clock. The data format is 8-bit, starting with the LSB.