1  General Description 
The EM78F734N is an 8-bit microprocessor designed and developed with low-power, high-speed CMOS technology and 
high noise immunity.  It has an on-chip 4K×13-bit Electrical Flash Memory and 128×8-bit In-system programmable 
EEPROM.  It provides three protection bits to prevent intrusion of user’s Flash memory code.  
With its enhanced Flash-ROM feature, the EM78F734N provides a convenient way of developing and verifying user’s 
programs.  Moreover, this Flash-ROM device offers the advantages of easy and effective program updates, using 
development and programming tools.  Users can avail of the ELAN Writer to easily program their development codes. 
 
2  Features 

 CPU Configuration 
••••  4K×13 bits Flash memory 
••••  144×8 bits on-chip registers (SRAM) 
••••  128 bytes In-system programmable EEPROM 
••••  8-level stacks for subroutine nesting 

 I/O Port Configuration 
••••  Three bidirectional I/O ports 
••••  Wake-up port : P6 
••••  12 Programmable pull-down I/O pins 
••••  Eight programmable pull-high I/O pins 
••••  Four programmable open-drain I/O pins 
••••  External interrupt : P60 

 Operating Voltage Range: 
••••  2.2V~5.5V @ – 40°C ~85°C (Industrial) 
••••  2.2V~5.5V @ 0°C ~70°C (Commercial) 

 Operating frequency range (base on two clocks): 
••••  IRC Drift Rate (Vdd @ 3.3V) 
••••  IRC Drift Rate (Temperature: -10°C+40°C) 

 One 16-bit Timer/Counter 
••••  TC1 : Timer/Counter/Capture 

 One 8-bit Timer/Counter 
••••  TC3 : Timer/Counter/PDO (Programmable 
Divider Output) / PWM (Pulse Width 
Modulation)  
Internal RC 
Frequency 
Drift Rate 
Temperature  
(-10°C+40°C) 
Process  Total 
455kHz  ±1%  ±1%  ±2% 
1 MHz  ±1%  ±1%  ±2% 
4 MHz  ±1%  ±1%  ±2% 
8 MHz  ±1%  ±1%  ±2% 
Internal RC 
Frequency 
Drift Rate 
Voltage 
(3.0~3.6V) 
Process  Total 
455kHz  ±1%  ±1%  ±2% 
1 MHz  ±1%  ±1%  ±2% 
4 MHz  ±1%  ±1%  ±2% 
8 MHz  ±1%  ±1%  ±2% 

 Eight available interrupts: 
••••  Internal interrupt: 4 
••••  External interrupt: 4 

 Seven channels Analog-to-Digital Converter with 
12-bit resolution 

 Peripheral Configuration 
••••  8-bit real Timer Clock/Counter (TCC) with 
selective signal sources, trigger edges, and 
overflow interrupt 
••••  Power down (Sleep) mode 
••••  Four programmable Level Voltage Reset (LVR) 
(LVR) : 3.3V, 3.0V, 2.6V, and 2.0V (POR) 
••••  Three security registers to prevent intrusion of 
Flash memory codes 
••••  One configuration register to accommodate 
user’s requirements 
••••  Two clocks per instruction cycle 
••••  High EFT immunity 
••••  Two sub-frequencies; 128kHz and 16kHz,  
the 16kHz is provided by dividing the 128kHz 

 Single instruction cycle commands 

 Five Crystal Range in Oscillator Mode 
Crystal Range  Oscillator Mode 
20 MHz ~ 12 MHz  HXT2 
12 MHz~6 MHz  HXT1 
6 MHz ~ 1 MHz  XT 
1 MHz ~ 100kHz  LXT1 
32.768kHz  LXT2 

 Programmable free running Watchdog Timer 

 Package Type:  
••••  16-pin DIP 300mil  :  EM78F734ND16 
••••  16-pin SOP 300mil  :  EM78F734NSO16 
••••  16-pin SSOP 150mil  :  EM78F734NSS16 
••••  18-pin DIP 300mil  :  EM78F734ND18 
••••  18-pin SOP 300mil  :  EM78F734NSO18 
••••  20-pin DIP 300 mil  :  EM78F734ND20 
••••  20-pin SOP 300mil  :  EM78F734NSO20 
 
Note: These are Green Products which do not contain  
hazardous substances.