SNC520

One Channel Direct Drive Speech Controller

5 FUNCTION DESCRIPTIONS

5.1. Oscillator

SNC520 accept RC type oscillator for system clock. The typical circuit diagram for

oscillator is listed as follow.

OSC

VCC

RC Oscillator

5.2. ROM

SNC520 contains substantial 32K word (10-bit) internal ROM. Program and voices

are shared with this same 32K word ROM.

5.3. RAM

SNC520 contains 64 nibbles RAM. The 64 nibbles RAM are divided into four pages

(page 0 to page 3, 16 nibble RAM on each page).

In our programming structure,

users can easily define and locate RAM page in the program. For instance, users can

use the instructions, PAGEn (n=0 to 3) to switch and indicate the RAM page. Besides,

users can use direct mode, M0 ~ M15 in the data transfer type instructions, to access

all 16 nibbles of each page.

5.4. Power Down Mode

“End” instruction will power down SNC520 and enable IC to consume fewer current for

power saving. (<3uA @VDD=3V and <5uA @VDD=5V) Please be aware that when

the power down mode is activated in SNC520, any valid data transition (L H or H L)

occurring on any IO ports (P2 and P3) will lead SNC520 back to normal operation

mode.

5.5. Sampling Rate Counter

The unique sampling rate counter is designed in voice channel to be able to play

diverse voices at different sample playing rates. The playing rate can be adaptively

set up among from the wide ranges of 2.5KHz to 20KHz. This feature makes voice

close to its original source and yield the better voice quality.

Ver: 1.4

June 8, 2005

3