SM1124 Datasheet, PDF (4/10 Pages) Nippon Precision Circuits Inc – Multimelody IC for Pagers

CLK input clock
SM1124 Series
CLK
t CWH
t CLK
t CWL
VIH
0.5VDD
VIL
SC input clock
SC
t SWH
t SC
t SWL
VIH
0.5VDD
VIL
Serial input
VIH
SC
0.5VDD
VIL
t DS
t DH
VIH
SI
0.5VDD
VIL
FUNCTIONAL DESCRIPTION
Control Functions
External reference clock
The SM1124 can operate at 12 selectable external
reference clock frequencies. Of these, 8 are
selectable for each tune. When multiple external
clock frequencies are input to a single IC, the clock
must be switched during playback mode. Note that
when the frequency in parentheses is selected, all
tunes can only be played using that single fixed
frequency.
• 32.768 kHz system: 32.768 kHz, 65.536 kHz,
(131.072 kHz)
• 37.5 kHz system: 37.5 kHz, 75.0 kHz,
(150.0 kHz)
• 38.4 kHz system: 38.4 kHz, 76.8 kHz,
(153.6 kHz)
• 48.0 kHz system: 48.0 kHz, 96.0 kHz,
(192.0 kHz)
The external reference clock input is used at any time
as well as during playback mode. If a clock signal is
input when not in playback mode (when ST is
LOW), the gate circuit switches to cutoff the external
reference clock signal from entering the device,
preventing unwanted current flow.
NIPPON PRECISION CIRCUITS—4