DESCRIPTION
The SM3504 is a CMOS 4-bit single-chip microcomputer for databank incorporating data memory RAM, LCD driver, key input circuit and buzzer output circuit. By connecting an external crystal, a 1Hz timer interrupt is made possible for easier clock function.

FEATURES
• ROM capacity :
   Program ROM 6 k x 23 bits
   Character ROM 5 x 8 x 128 bits
• RAM capacity :
   Working RAM 256 x 4 bits
   Display RAM 60 x 8 bits
   Data RAM 512 x 8 bits
• LCD display : 60-segment x 8-common
• I/O ports :
   Buzzer output 1 bit (4 kHz)
   Key input 7 bits
• Standby release : 2 events (2 Hz signal, key input)
• Built-in oscillator :
   System clock (built-in CR oscillator) 250 kHz
   Timer (built-in CR oscillator) 32.8 kHz
   (external crystal) 32.768 kHz
• Instruction cycle time : 12 µs
• Operating temperature : –10 to +60°C
• Supply voltage : 2.5 to 3.4 V
• Package : 80-pin QFP (QFP080-P-1420)