1. INTRODUCTION

SNC745 is a 64mins two-channel speech/melody and 4-channel wave-table melody voice chip. It based on reduced 16-bit fixed-point DSP architecture. SNC745 provides user some necessary and efficient DSP instructions. Furthermore, SNC745 provide one 10-bit PWM and one 10-bit DA converter to driving speaker for speech/melody output. User can select PWM or DA by programming DA/PWM control register, and only one function can be active at the same time.

2. FEATURES

♦ Power supply: 2.4V ~ 3.6V (for 2 battery application)

                     3.6V ~ 5.1V (for 3 battery application)

♦ Built-in a 16-bit DSP (Very Light Structure)

♦ Software-based voice/melody processing

♦ Rich Function Instruction Set

♦ System Clock

   − 16MHz crystal or R-C type oscillator for system clock

   − 0.25s real time clock is form 32768Hz crystal

♦ 8 MIPS CPU performance

♦ I/O Ports:

   − 16 I/O pins (P0.0~P0.15) and 8 input pins (P1.0~P1.7)

   − P0.15 with IR carrier signal

♦ RAM size: 2K*16 bits

♦ High performance program ROM: 32K*16 bits

♦ Data ROM size: 480K*16 bits

♦ Total ROM size: 512K*16 bits

♦ Maximum program size: 64K word

♦ 8 Interrupt Sources

   − 4 for Internal Timer (timer0, 1, 2 and RTC)

   − 4 for External (P0.0~P0.3)

♦ Two voice/melody channels

♦ Three 8-bit timer with auto-reload function

♦ Built in a 10-bit PWM Direct Drive circuit and a fixed current D/A output

♦ Sampling Rate: 8KHz ~16KHz

♦ Built-in software voice synthesizer (multiple bit-rate solution 2Kbps, 2.8Kbps, 3.6Kbps, 8Kbps, 10Kbps, 12Kbps, 14Kbps, 16Kbps, 20Kbps, 24Kbps, and 29Kbps @8K, 10K, 12K, 14K, 16K sampling rate)

♦ Built-in software melody synthesizer includes the dual-tone melody and 4-ch wave-table melody.

♦ Low Voltage Reset