GENERAL DESCRIPTION
EM78P156EH is an 8-bit microprocessor designed and developed with low-power and high-speed CMOS technology. It is equipped with 1K*13-bits Electrical One Time Programmable Read Only Memory (OTP-ROM). It provides a PROTECTION bit to prevent user’s code in the OTP memory from being intruded. 6 OPTION bits are also available to meet user’s requirements. With its OTP-ROM feature, the EM78P156EH is able to offer a convenient way of developing and verifying user’s programs. Moreover, user can take advantage of EMC Writer to easily program his development code.

FEATURES
• Operating voltage range : 3.2V~5.5V
• Operating temperature range: 0°C~70°C
• Operating frequency rang (base on 2 clocks ):
   * Crystal mode: DC~20MHz at 5V, DC~8MHz at 3.2V.
   * ERC mode: DC~4MHz at 5V, DC~4MHz at 3.2V.
• Low power consumption:
   * Less then 1.6 mA at 5V/4MHz
   * Typically 20 µA at 3V/32KHz
   * Typically 1 µA during sleep mode
• 1K × 13 bits on chip ROM
• One security register to prevent intrusion of OTP memory codes
• One configuration register to accommodate user’s requirements
• 48× 8 bits on chip registers (SRAM, general purpose register)
• 2 bi-directional I/O ports
• 5 level stacks for subroutine nesting
• 8-bit real time clock/counter (TCC) with selective signal sources, trigger edges,
   and overflow interrupt
• Two clocks per instruction cycle
• Power down (SLEEP) mode
• Three available interruptions
   * TCC overflow interrupt
   * Input-port status changed interrupt (wake up from sleep mode)
   * External interrupt
 • Programmable free running watchdog timer
• 8 programmable pull-high pins
• 7 programmable pull-down pins
• 8 programmable open-drain pins
• 2 programmable R-option pins
• Package types:
   * 18 pin DIP 300mil : EM78P156EHP
   * 18 pin SOP 300mil : EM78P156EHM
   * 20 pin SSOP 209mil : EM78P156EHAS
   * 20 pin SSOP 209mil : EM78P156EHKM
• 99.9% single instruction cycle commands
• The transient point of system frequency between HXT and LXT is around 400KHz