DESCRIPTION
S3C1840, a 4-bit single-chip CMOS microcontroller, consists of the reliable SMCS-51 CPU core with on-chip ROM and RAM. Eight input pins and 11 output pins provide the flexibility for various I/O requirements. Auto reset circuit generates reset pulse every certain period, and every halt mode termination time. The S3C1840 microcontroller has been designed for use in small system control applications that require a low-power, cost - sensitive design solution. In addition, the S3C1840 has been optimized for remote control transmitter.

FEATURES
ROM Size
· 1,024 bytes

RAM Size
· 32 nibbles

Instruction Set
· 39 instructions

Instruction Cycle Time
· 13.2  msec at fxx = 455 kHz

Input Ports
· Two 4-bit ports (24 pins)/one 4-bit port, one 2-bit ports (20 pins)

Output Ports
· One 4-bit port, seven 1-bit ports (24 pins)/one 4-bit port, five1-bit ports (20 pins)

Built-in Oscillator
· Crystal/ceramic resonator
Built-in Reset Circuit
· Built-in Power-on reset and auto reset circuit for generating reset pulse every 131072/fxx (288 ms at fxx = 455 kHz)

Four Transmission Frequencies
· fxx/12 (1/4 duty), fxx/12 (1/3 duty), fxx/8 (1/2 duty), and no-carrier frequency

Supply Voltage
· 1.8 V-3.6 V (250 kHz ≤ fOSC ≤ 3.9 MHz)
  2.2 V-3.6 V (3.9 MHz < fOSC ≤ 6 MHz)

Power Consumption
· Halt mode: 1 mA (maxium)
· Normal mode: 0.5 mA (typical)

Operating temperature
· – 20 °C to 85 °C

Package Type
· 24 SOP, 20 DIP, 20 SOP

Oscillator Frequency divide select
· Mask Option: fxx = fOSC or fOSC/8