DocID024329 Rev 1
3/8
UM1615
Description
8
2.1
Use of the demonstration board
The ST8034C demonstration board is designed both for standalone operation or to be fully
controlled by the microcontroller; it is fully configurable and provides access to all the
signals including supply voltages through labeled test points and uses a standard connector
for a simple communication interface with the microcontroller block. The labeled test points
on the board are in the same order as the signals in the flat interface cable.
For an easy connection of oscilloscope probes to the test points, remove the plastic tip with
the hook from the probes and insert the center pin into the test point terminal. Ground test
points are available in a sufficient amount throughout the board.
2.2 Smartcard
interface
The demonstration board contains a full size smartcard connector. Insert the smartcard from
the right-hand side, card contacts facing down. Card presence detection is implemented
(a presence switch inside the card connector, normally open).
2.3
Interface to a microcontroller block
A standard 16-pin header connector with a standard cable is used to interconnect the
ST8034C demonstration board module with a microcontroller block. The voltage level for
communication on this interface is V
DD(INTF)
.
2.4
Default functionality notes
No floating pins: for simple standalone testing, all the input signal levels are softly
defined by pull-up or pull-down resistors on the board, refer to
Figure 4: Schematic
diagram
.
The PORADJ undervoltage threshold on the V
DD(INTF)
supply voltage (UVLO) is set by
R1 and R2 to 1.5 V typ. The resistors can be replaced with different values to set
different undervoltage thresholds on V
DD(INTF)
:
V
DD(INTF)
UVLO threshold (falling) = (R1 + R2) / R2 x V
TH(PORADJ)
V
DD(INTF)
UVLO threshold (rising) = (R1 + R2) / R2 x (V
TH(PORADJ)
+ V
HYST(PORADJ)
)
For detailed specifications of the voltage threshold values, refer to Table 7 of the
ST8034C datasheet.
The sum of R1 + R2 should be about 100 k
, which is a good compromise between
a sufficient robustness and a minimum current consumption.
Please consider tolerance ranges of the resistors used in the resistor divider and
specifications range of the V
TH(PORADJ)
to make sure that even in the worst case the
real V
DD(INTF)
undervoltage deactivation threshold does not fall in the desired operating
voltage range (i.e. consider also voltage supply tolerance range).
