SN66040B

4-Channel Speech Controller

5 FUNCTION DESCRIPTIONS

5.1. Oscillator

SN66040B accepts crystal oscillator / ceramic resonator or RC type oscillator

(selected by pin CKSEL) for system clock. The typical circuit diagrams for oscillator

are listed as follows.

OSC/XIN

CKSEL

XOUT

VDD

RC Oscillator

Crystal / Resonator

VDD

OSC/XIN

CKSEL

XOUT

20pf

20pf

2MHz

5.2. ROM

SN66040B contains 128K word (12-bit) internal ROM. Program, voices, melodies,

data, and instrument waveforms share the same ROM with the others.

5.3. RAM

SN66040B contains 128 nibble RAM. The 128 nibble RAM is separated into two

pages (page 0 and page 1). An implicit page indicator is utilized to specify page

address. Two instructions, PAGE0 and PAGE1, can switch the page indicator. All 64

nibbles of each page can be accessed by direct mode (to specify M0 ~ M63 in the data

transfer type instructions.)

5.4. Power Down Mode

“End” instruction will let SN66040B enter power down mode and consumer very little

amount of current. (<2uA @VDD=3V and <5uA @VDD=5V) After SN66040B enters

power down mode, any valid data transition (L H or H L) occurring on any input

ports or IO ports (P1, P2, and P3) lead SN66040B back to normal operation mode.

Ver: 1.1

December 6, 2004

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