EM78P157N is an 8-bit microprocessor designed and developed with low-power, high-speed CMOS technology. It is equipped with 1K x 13-bits Electrical One Time Programmable Read Only Memory (OTP-ROM). It provides three PROTECTION bits to prevent user's code in the OTP memory from being intruded. Eight OPTION bits are also provided to meet user's additional requirements.

With its OTP-ROM feature, the EM78P157N is able to offer a convenient way of developing and verifying user's programs. Moreover, user can take advantage of ELAN Dwriter to easily program his development code.

• Operating voltage range: 2.5V ~ 5.5V
• Operating temperature range: -40°C ~ 85°C
• Operating frequency range (base on 2 clocks ):
  * Crystal mode: DC ~ 20MHz at 5V, DC ~ 8MHz at 3V, DC ~ 4MHz at 2.5V
  * ERC mode: DC ~ 4MHz at 5V, DC ~ 4MHz at 3V, DC ~ 4MHz at 2.5V
• Low power consumption:
  * Less then 2 mA at 5V/4MHz
  * Typically 20 μA at 3V/32KHz
  * Typically 1 μA during sleep mode
• 1K x 13 bits on chip ROM
• One security register to prevent intrusion of OTP memory codes
• One configuration register to accommodate user's requirements
• 48 x 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:
  * 14 pin DIP 300mil : EM78P157NBP
  * 14 pin SOP 150mil : EM78P157NBM
  * 18 pin DIP 300mil : EM78P157NAP
  * 18 pin SOP 300mil : EM78P157NAM
  * 20 pin SSOP 209mil : EM78P157NAAS
  * 20 pin SSOP 209mil : EM78P157NAKM
• 99.9% single instruction cycle commands
• The transient point of system frequency between HXT and LXT is around 400KHz