EF6802

The EF6802 has the following features including On-Chip Clock Circuit;128x8 Bit On-Chip RAM;32 Bytes of RAM are Retainable;Software-Compatible with the EF68Q0;Expandable to 64K Words;Standard TTL-Compatible Inputs and Outputs;8-Bit Word Size;16-Bit Memory Addressing;Interrupt Capability.

The EF6802 is a monolithic 8-bit microprocessor that contains all the regisiters and accumulators of the present EF6800 plus an internal clock oscillator and driver on the same chip. In addition, the EF6802 has 128 bytes of on-board RAM located at hex addresses $0000 to $007F.The first 32 bytes of RAM,at hex addresses $0000 to $001F,may be rerained in a low power mode by utilizing Vcc standby;thus,facilitating memory retention during a power-down situation.The EF6802 is completely software compatible with the EF6fl00 as well as the entire EF6800 family of parts. Hence, the EF6802 is ex.pandable to 64K words. This block diagram shows a typical cost etlective  microcomputer.  The  MPU  is the center of the microcomputer system and is shown in a minimum system interfacing with a ROM combination chip. It is not intended that this system 6e limited to this function but that it be expandable with other parts in the 6800 Mfcrocomputer family.This input contains circuitry to protect the inputs against damage due to high static voltages or electric fields; however, it is advised that normal precautions be taken to avoid application of any voltage higher than maximum  rated  voltages  to  this  high-Impedance circuit. Reliability of operation is enhanced if unused inputs are tied to an appropriate logic voltage level le.g., either VSS or VCCI.

A general block diagram of the EF6802 is shown in Figure 6. As shown, the number and configuration of the registers are the same as for the eroauu.The 128x8-bit RAM` has been added to the basic MPU. The first 32 bytes can be retained during power-up and power-down conditions via the RE signal.The EF6808 is identical to the EF6802 except for on-board RAM. Since the EF6808does not have on-board RAM pin 36 must be tied to ground allowing the processor to utilize up to 64K bytes of external memory.