SNC668
4-Channel Speech Controller
5. FUNCTION DESCRIPTIONS
5.1 Oscillator
SNC668 accepts crystal oscillator / ceramic resonator or RC type oscillator (selected
by pin CKSEL) for system clock. The typical circuit diagrams for oscillator are listed as
follows.
VDD
S NC 668
15pF
S NC 668
8MHZ
CKS EL
XOUT/ROS C
XIN
CKS EL
XO UT/RO S C
XIN
100K
8MHZ Crystal
15pF
8M Rosc
5.2 ROM
SNC668 contains 96K words (12-bit) internal ROM. Program, voices, melodies, data,
and instrument waveforms share the same ROM with the others.
5.3 RAM
SNC668 contains 256 nibble RAM. The 256 nibble RAM is separated into four pages
(page 0, page1, page2 and page 3). An implicit page indicator is utilized to specify
page address. Four instructions, PAGE0, PAGE1, PAGE2 and PAGE3, can switch
the page indicator. All 64 nibbles of each page can be accessed by direct mode (to
specify M0 ~ M63 in the data transfer type instructions.)
5.4 Power Down Mode
“End” instruction will let SNC668 enter power down mode and consumer very little
amount of current. (<3uA @VDD=3V and <5uA @VDD=5V) After SNC668 enters
power down mode, any valid data transition (L H or H L) occurring on any IO ports
(P1 to P6) lead SNC668 back to normal operation mode.
5.5 Sampling Rate Counters
4 independent sampling rate counters are dedicated to 4 individual voice channels to
play voices with different playing rates. The playing rate is programmable from 4KHz
to 40KHz. The resolution of sampling period of each sampling rate counter is 0.25 uS.
This feature helps SNC668 play sounds with accurate pitches in the case of music
instrument synthesis.
Ver: 1.3
5
June 8, 2005
SONIX [ SONIX TECHNOLOGY COMPANY ]
