1.1 S3C8/S3F8 Series Microcontrollers
Zilog's S3C8/S3F8 Series of 8-bit single-chip CMOS microcontrollers offers a fast and efficient CPU, a wide range
of integrated peripherals, and various mask-programmable ROM sizes. Important CPU features include:
• Efficient register-oriented architecture
• Selectable CPU clock sources
• Idle and Stop power-down mode release by interrupt
• Built-in basic timer with watchdog function
A sophisticated interrupt structure recognizes up to eight interrupt levels. Each level can have one or more
interrupt sources and vectors. Fast interrupt processing (within a minimum of four CPU clocks) can be assigned to
specific interrupt levels.
1.2 S3F8S28/S3F8S24 Microcontroller
The S3F8S28/S3F8S24 single-chip CMOS micro-controller is fabricated using a highly advanced CMOS process
and is based on Zilog's newest CPU architecture. Its design is based on the powerful SAM8RC CPU core. Stop
and idle (power-down) modes were implemented to reduce power consumption.
The S3F8S28/S3F8S24 is a micro-controller with 8K/4Kbyte multi-time-programmable Flash ROM embedded.
Using the SAM8RC design approach, the following peripherals were integrated with the powerful core:
• Three configurable I/O ports (22 pins)
• 18 interrupt sources with 18 vectors and 8 interrupt levels
• A 16-bit Timer 0 with one 16-bit timer or two 8-bit timer mode.
• A 16-bit Timer 1 with interval & Capture function.
• A free running Watchdog Timer with interrupt and Reset.
• Analog to digital converter with thirteen input channels (MAX.) and 12-bit resolution
• One UART module
• One IIC module
• Two PWM outputs with three optional mode: 12-bit (6 + 6); 8-bit (6 + 2); 14-bit (8 + 6);
The S3F8S28/S3F8S24 microcontroller is ideal for use in a wide range of electronic applications requiring simple
timer/counter, PWM, ADC. S3F8S28/S3F8S24 is available in a 24/20-pin SOP Package and a 24-pin TSSOP
package and a 20-pin DIP package.

1.3 Features
• CPU
− SAM8RC CPU core
• Memory
− Internal multi-time program Full-Flash memory:
8K  8 bits program memory (S3F8S28)
4K  8 bits program memory (S3F8S24)
o Sector size: 128 bytes
o User programmable by "LDC" instruction
o Sector erase available
o Fast programming time
o External serial programming support
o Endurance: 10,000 erase/program cycles
o 10 Years data retention
− 272byte general-purpose register area
• Instruction Set
− 78 instructions
− Idle and Stop instructions added for power-down modes
• Instruction Execution Time
− 333ns at 12MHz fOSC (minimum)
• Interrupts
− 8 interrupt levels and 17 interrupt sources (8 external interrupt and 9 internal interrupt)
− Fast interrupt processing feature
− Watchdog interrupt can release Stop Mode.
• General I/O
− Three I/O ports (Max. 22 pins)
− Bit programmable ports
• 2-ch High-speed PWM with Three Selectable Resolutions
− 12-bit PWM: 6-bit base + 6-bit extension
− 8-bit PWM: 6-bit base + 2-bit extension
− 14-bit PWM: 8-bit base + 6-bit extension