msm9802 Oki Semiconductor, msm9802 Datasheet - Page 15

• Manufacturer Part Number: msm9802
• Description: Voice Synthesis Ic With Built-in Mask Rom
• Manufacturer: Oki Semiconductor

If playback is attempted at an unused address in the phrases, AOUT goes to 1/2 I
Figure 3.2 shows the timing.
In the SW input interface, no phrase is triggered when SW2 to SW0 are all set to “0”. Therefore, when the circuit
consists of a diode matrices that use push-button switches, the maximum playback phrases are 56 phrases.
Random playback function
The random playback function randomly generates 15 different addresses corresponding to the four bits of the
addresses of A0 and SW2-SW0 (except ALL "L") on the IC, after which playback commences.
Therefore, any input to A0 and SW2 to SW0 pins from external control is invalid. Hold these 4 pins either “H” or
“L” level. SW2 to SW0 pins may be held open as they have internal pull-down resistor.
Playback may not occur if all the 15 addresses have not been assigned a phrase. Care must be taken when creating
ROM data.
For example, when four phrases, “sunny”, “rainy”, “cloudy”, and “snowy”, are to be played randomly, set the
phrases as shown in Table 3.1 in which a phrase is assigned to all the 15 addresses. The four phrases are then
played back at random as shown below.
OKI Semiconductor
SW2-SW1 (I) “L”
Figure 3.2 Timing when Playback is Attempted at an Unused Phrase Address
AOUT (O)
BUSY (O)
A2-A0 (I)
SW0 (I)
Oscillation start
8 codes
A2-A0
000
001
002
111
to
×
×
SW2-SW0
7 codes
(000)
001
002
111
to
= 56
Code Prohibited
= 56 Phrases
AOUT
and playback does not occur.
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