EM91450A EMC [ELAN Microelectronics Corp], EM91450A Datasheet - Page 3

• Manufacturer Part Number: EM91450A
• Description: TONE/PULSE DIALER WITH LCD INTERFACE AND I.P.P. DETECT FUNCTION
• Manufacturer: EMC [ELAN Microelectronics Corp]

FUNCTIONAL BLOCK DIAGRAM
PIN DESCRIPTIONS
* This specification are subject to be changed without notice.
ROW1~ROW4
COL1~COL3
COL4/KT
XIN and XOUT
XMUTE
V
HFI
HFO
DTMF
DD
Symbol
and V
SS
Keyboard scan pins of row group. In idle state (HKS is "High" and HFO is "Low"),
Keyboard scan pins of column group. In idle state, these pins stay "High impedance"
Oscillator input and output pins. A 3.579545 MHz crystal or ceramic resonator must
Input/Output structure pin. The output is a open drain structure. Input is schmitt trigger
COL4/KT
these pins stay ÒHigh impedanceÓ level to prevent power consumption. Otherwise,
these pins switch to ÒHighÓ level for detecting keyboard entry. These pins will output
600 Hz signal while keyboard is scanning.
level. Otherwise these pins switch to ÒLowÓ level for detecting keyboard entry. These
pins will output 600 Hz signal while keyboard is scanning.
The fourth column group pin of the keyboard that also provides the keytone output
. Normally, this pin stays "Low" level for detecting keyboard entry. After a valid
keyboard entry, this pin will output keying confirmation tone that is 600 Hz signal and
30 ms duration. To prevent signal interference, while DTMF issue, it will disable key
tone output except function key.
be crossed connection to XIN and XOUT pins which generate system clock.
structure. This pin will be input pin during ON-HOOK status for illegal parallel phone
detect input pin and will be output pin in OFF-HOOK condition for control speech
network.
Positive and negative power supply input pins. Recommended operating voltage from
2.0Vdc to 5.5Vdc.
Handfree inputs pin which accepts falling edge signal to turn "on" or turn "off"
handfree function. This pin is hysteresis input structure and built-in pull up resistor
(typically 200 Kohms).
Handfree outputs pin that is designed to control telephone line for on-hook dialing or
control speakerphone circuit for handfree conversation. When handfree function is
executed, this pin will switch to"High". Otherwise, this pin stays "Low" level.
The DTMF (Dual Tone Multi-Frequency) and music signals output pin. Normally,
this pin stays "Low" level. In Tone dialing mode, this pin will output DTMF signal
that is corresponding to keyboard 0 .. 9, * and # keys.
XMUTE
XOUT
ROW1
ROW4
COL1
COL2
COL3
XIN
I/O circuit
Oscillator
Keyboard
Keyboard
(column)
interface
interface
(Row)
VDD
SDO
HFI
Timing/Control circuit
Output circuit
HFO HDO
Input circuit
Function
HKS
TONE/PULSE DIALER WITH LCD INTERFACE
Memory
RMUTE
DRING
decoder
generator
latch
programming counter
Pulse
&
AND I.P.P. DETECT FUNCTION
Row/Column
converter
D/A
EM91450 SERIES
PO
DTMF
2.10.1999
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