SNC20AS

Direct Drive Speech Controller

Ver: 0.3

Sept 20, 2007

4

5.

5.

5.

5.

FUNCTION DESCRIPTIONS

5.1. Oscillator

SNC20AS accept RC type oscillator for system clock. The typical circuit diagram for

oscillator is listed as follow.

5.2. ROM

SNC20AS contains substantial 256K words (10-bit) internal ROM. Program, voices

and other data are shared with this same 256K words ROM.

5.3. RAM

SNC20AS contains 48 nibbles RAM. The 48 nibbles RAM are divided into three

pages (page 0, page 1 and page 2, 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 2) to switch and indicate the RAM page.

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

(M15 is forbidden using for user in each page), to access all 16 nibbles of each page.

5.4. Power Down Mode

“End” instruction will power down SNC20AS 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 SNC208, any valid data transition (L

H or

H

L) occurring on any IO pins of P3 and P2 will lead SNC20AS back to normal

operation mode.

5.5. Sampling Rate Counters

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.

OSC

VCC

RC Oscillator