OKI Semiconductor
FEDL2250DIGEST-04
Issue Date: April. 20, 2004
ML2251/52/53/54/56-XXX, ML22Q54
2-Channel Mixing Oki ADPCM Algorithm-Based Speech Synthesis LSI
This document contains minimum specifications. For full specifications, please contact your nearest Oki office or
representative.
GENERAL DESCRIPTION
The ML2250 family is a 2-channel mixing speech synthesis device with an on-chip voice data (i.e., phrases)
storing mask ROM and a flash memory. Besides playing the built-in voice data, this device can output voice data
that is input from outside the device. This ML2250 family allows to select the playback method from the 8-bit
PCM, non-linear 8-bit PCM, 16-bit PCM, 2-bit ADPCM2, and 4-bit ADPCM2 algorithms. And the sound volume
is adjustable as well.
The ML2250 family incorporates a 14-bit D/A converter and low-pass filter.
It is easy to configure a speech synthesizer by externally connecting a power amplifier and a CPU to the ML2250
family.
The ML2250 family line-up includes 2 types of products: with on-chip mask ROM, and with on-chip flash
memory.
• ML2251/52/53/54/56-XXX
This is a CMOS single chip speech synthesis device with an on-chip mask ROM. Products with 2 types of mask
ROMs are available in the ML2250 family depending upon the total playback time length.
• ML22Q54
The ML22Q54 is a speech synthesis device with a 4-Mbit flash memory built in. The voice data can be easily
written to the flash memory using a special tool. The on-chip flash memory product is suitable for the diversified
low volume production or short delivery time applications that the on-chip mask ROM product cannot support.
The ML22Q54 is most suitable for evaluation because the circuit configuration is the same as the on-chip mask
ROM product.
A combination of fixed and variable messages can be written because it is easy to write to the built-in flash
memory. It is also possible to store and read data, other than voice, to/from an area in the flash memory not used
as voice data.
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