HT38A5 Holtek Semiconductor Inc., HT38A5 Datasheet - Page 4

• Manufacturer Part Number: HT38A5
• Description: Ht38a5 -- 12 Melody Music Generator
• Manufacturer: Holtek Semiconductor Inc.

A.C. Characteristics
Function Description
Key Control Mode
Communication with External MCU Control Mode (Clock Mode) Communication with External CPU
Rev. 1.00
MCU interface
f
f
t
t
Mode selection
Low voltage detect
PA1: Melody select key
PA2: Volume key
PA3: Telephone Hold key
PA6: Ring Detect
PA7: Hook Detect
PA6:clock pin
PA7:data pin
OSC
SYS
WDT
RES
Symbol
System Frequency
System Clock
Watchdog Time-Out Period (RC)
External Reset Low Pulse Width
Parameter
PA0=0, key control mode
PA0=1, MCU control mode
PA4=0,(normal) ;PA4=1(low voltage active, program stop)
This key chooses and plays one of the 12 stored musical melodies. When the key is
pressed the next melody in the list will be selected and played. When the HOLD key
is pressed the telephone hold function will be activated and when an incoming ring
signal is detected the music will be played.
Controls the music volume in 8 discrete steps. Each time the key is pressed the vol-
ume will reduce one step at a time until the lowest volume is reached. When the low-
est volume is reached, the next key press will return the volume to its maximum level.
If this key is pressed during a phone conversation the phone will be put on hold and
the caller can listen to the music while waiting. If, when the music is playing, the hand-
set is lifted, the music will immediately stop playing. After this happens the HOLD
function will have no effect for a period of 2 seconds.
When an incoming 13Hz~90Hz ring signal is detected after a period of 200ms, the
music will automatically start playing. When the incoming ring signal stops, after a pe-
riod of 6 seconds the music will stop playing.
This line detects the on/off hook condition of the telephone. Only when the telephone
is in an on-hook condition, can the music be chosen and played. If the handset is
lifted to talk, the music will stop playing and the HOLD key will be effective.
Clock from external CPU
Data from external CPU
V
5V
5V
DD
8MHz crystal
Without WDT prescaler
Test Conditions
4
Conditions
Min.
4
9
1
Typ.
17
8
November 2, 2006
Max.
35
8
HT38A5
Ta=25 C
MHz
MHz
Unit
ms
s