HD44820

The HD44820 is designed as the CMOS 4-bit single chip microcomputer which contains ROM, RAM, I/O and timer /event counter on single chip. It is designed to perform efficient controller function as well as arithmetic function for both binary and BCD data. The CMOS technology of it provides the flexibility of microcomputers for battery powered and battery back-up applications.

It has sixteen features. (1)4-bit architecture. (2)2048 words of program ROM (10bits/word) and 128 words of attern ROM (10 bits/word). (3)160 digits of data RAM (4 bits/digit). (4)44 IO lines and 2 external interrupt lines. (5)Timer /event counter. (6)Instruction cycle time 10us. (7)All instructions except one instruction, single word and single cycle. (8)BCD arithmetic instructions. (9)Pattern generation instruction. (10)Powerful interrupt function 3 interrupt sources.(11)Bit manipulation instructions for both RAM and IO. (12)Option of IO configuration selectable on each pin; pull up MOS or CMOS or open drain. (13)Built-in oscillator. (14)Low operating power dissipation 2mW typ. (15)Standby mode (halt mode) 50uW max. (15)CMOS technology. (16)Single power supply 5V +/-10%. That are al the main features.

Some absolute maximum ratings have been concluded into several points as follow. (1)Its supply voltage would be from -0.3V to +7.0V. (2)Its pin voltage would be from -0.3V to Vcc+0.3V except for pins specified by Vt2. (3)Its pin voltage would be from -0.3V to +10V applied to only open-drain output pins and open-drain IO common pins. (4)Its maximum total output current would be 45mA. (5)Its operating temperature range would be from -20°C to +75°C. (6)Its storage temperature range would be from -55°C to +125°C. It should be noted that stresses above those listed in absolute maximum ratings may cause permanent damage to device and all voltages are with respect to GND. And so on. If you have any question or suggestion or want to know more information please contact us for details. Thank you!