Mobile Tech Co. Ltd 64MXFWBF110A Manuale Utente
18
SCLK duty cycle
SIMCLK Duty = 50%,
fsimclk = 5 MHz
fsimclk = 5 MHz
47
53
%
SCLK propagation
delay
delay
30
50
ns
Following is a reference circuit about SIM interface. We recommend a Electrostatic
discharge device ST (
) ESDA6V1W5 or ONSEMI (
)
SMF05C for “ESD ANTI”.
Figure
Figure
Figure
Figure4
4
4
4 The
The
The
The reference
reference
reference
reference design
design
design
design of
of
of
of SIM
SIM
SIM
SIM Socket
Socket
Socket
Socket
3.12.
3.12.
3.12.
3.12. Keypad
Keypad
Keypad
Keypad Interface
Interface
Interface
Interface
The keypad can be divided into two parts: one is the keypad interface including 5 columns
and 5 rows with one dedicated power-key, as shown in Fig.
and 5 rows with one dedicated power-key, as shown in Fig.
Fig.
Fig.
Fig. 5.
5.
5.
5. the other is the key detection
block which provides key pressed, key released and de-bounce mechanisms. Each time the
key is pressed or released, i.e. something different in the 5 x 5 matrix or power-key, the key
detection block senses the change and recognizes if a key has been pressed or released.
This keypad can detect one or two key-pressed simultaneously with any combination. Since
the key press detection depends on the HIGH or LOW level of the external keypad
interface, if keys are pressed at the same time and there exists a key that is on the same
column and the same row with the other keys, the pressed key cannot be correctly decoded.
For example, if there are three key presses: key1 = (x1, y1), key2 = (x2, y2), and key3 =
(x1, y2), then both key3 and key4 = (x2, y1) are detected, and therefore they cannot be
distinguished correctly. Hence, the keypad can detect only one or two keys pressed
simultaneously at any combination. More than two keys pressed simultaneously in a
specific pattern retrieve the wrong information.
There should not be an external pull down resistor on KCOL0 and please use the KCOL1-4
prior if could meet demand. Because KCOL0 connect to GND is used to enter USBDL
mode.
key is pressed or released, i.e. something different in the 5 x 5 matrix or power-key, the key
detection block senses the change and recognizes if a key has been pressed or released.
This keypad can detect one or two key-pressed simultaneously with any combination. Since
the key press detection depends on the HIGH or LOW level of the external keypad
interface, if keys are pressed at the same time and there exists a key that is on the same
column and the same row with the other keys, the pressed key cannot be correctly decoded.
For example, if there are three key presses: key1 = (x1, y1), key2 = (x2, y2), and key3 =
(x1, y2), then both key3 and key4 = (x2, y1) are detected, and therefore they cannot be
distinguished correctly. Hence, the keypad can detect only one or two keys pressed
simultaneously at any combination. More than two keys pressed simultaneously in a
specific pattern retrieve the wrong information.
There should not be an external pull down resistor on KCOL0 and please use the KCOL1-4
prior if could meet demand. Because KCOL0 connect to GND is used to enter USBDL
mode.