The EM78612 is a series of Universal Serial Bus 8-bit RISC microcontrollers. It is specifically designed for USB low speed device application and to support legacy device such as PS/2 mouse. The EM78612 also support one device address and two endpoints..
The EM78612 is implemented on a RISC architecture. It has five-level stack and six interrupt sources. The amount of General Input/Output pins is up to12. Each device has 80 bytes SRAM. The ROM size of the EM78612 is 2K. These series of chips have Dual Clock mode which allows the device to run on low power saving frequency.

Features

• Low-cost solution for low-speed USB devices, such as mouse, joystick, and gamepad.
• USB Specification Compliance
  * Universal Serial Bus Specification Version 1.1
  * USB Device Class Definition for Human Interface Device (HID), Firmware Specification Version 1.1
  * Support 1 device address and 2 endpoints (EP0 and EP1)
• USB Application
  * USB protocol handling
  * USB device state handling
  * Identifies and decodes Standard USB commands to EndPoint Zero
• PS/2 Application Support
  * Built-in PS/2 port interface
• Built-in 8-bit RISC MCU
  * 5 level stacks for subroutine and interrupt
  * 6 available interrupts
  * 8-bit real time clock/counter (TCC) with overflow interrupt
  * Built-in RC oscillator free running for WatchDog Timer and Dual clock mode
  * Two independent programmable prescalers for WDT and TCC
  * Two methods of power saving:
     - Power-down mode (SLEEP mode)
     - Low frequency mode.
  * Two clocks per instruction cycle
• I/O Ports
  * Up to 12 general purposes I/O pins grouped into two ports (Port 6 and 7).
  * Up to 2 LED sink pins
  * Each GPIO pin of Ports 6 & Port 7 has an internal programmable pull-high resistor
  * Each GPIO pin of Ports 6 has an internal programmable pull- low resistor
  * Each GPIO pin wakes up the MCU from sleep mode by input state change
• Internal Memory
  * Built-in 2048*13 bits MASK ROM
  * Built-in 80 bytes general purpose registers (SRAM)
  * Built-in USB Application FIFOs.
• Operation Frequency
  * Normal Mode: MCU runs on the external oscillator frequency
  * Dual Clock Mode: MCU runs at the frequency of 256 KHz (or 32KHz, 4KHz, 500Hz),
  emitted by the internal oscillator with the external ceramic resonator turned off to save power.
• Built-in 3.3V Voltage Regulator
  * For MCU power supply
  * Pull-up source for the external USB resistor on D-pin.
• Package Type
  * 16 pin PDIP(300MIL) / SOP(150MIL) (EM78612 AP / AM)
  * 18 pin PDIP(300MIL) / SOP(300MIL) (EM78612 BP / BM)
  * 20 pin PDIP(300MIL) / SOP(300MIL) (EM78612 CP / CM)
  * 20 pin SSOP(209MIL) (EM78612 FM)