The stack pointer is 16 bits in size on the 8085 because that is how Intel designed it. The address bus is also 16 bits, so it made sense for the program and stack to be located anywhere in that address space.
The program counter (PC) and stack pointer (SP) registers are 16-bit registers in the 8085 and in the 8086/8088 because that is how Intel designed the processors.
The various 16-bit registers on the 8085 are BC, DE, HL, SP, PC.
Because Intel designed it that way. The 8085 was designed as a 8 bit computer in a 16 bit address space. This means that the PC (Program Counter) and SP (Stack Pointer) should be 16 bits in size.
Program Counter( PC)stores the 16-bit memory address of the next instruction to be fetched. Stack Pointer (SP)stores the address of a memory location which is used as a stack.
pc and stack pointer
Because that's how Intel designed it. Even though the 8085 is an 8-bit computer, the program counter and stack pointer are 16 bits wide in order to support the address bus, which is also 16 bits wide. In the case of the 8086/8088, the program counter and stack pointer are still 16 bits wide, even though the address bus is 20 bits wide, because the 8086/8088 adds segmentation through the 16 bit segment register which is left shifted by 4.
The stack size of Intel's 8085 microprocessor is theoretically 64 kb, but the real limit is a function of memory and program architecture and layout. The stack pointer is 16 bits, but that is not the same as stack size.
The 8085 was replaced with the 8086/8088. As such, there is no 16 bit version of the 8085.
The most significant difference between the Intel 8085 and 8086 microprocessors is that the 8085 is an 8-bit system and the 8086 is a 16-bit system. This difference allows the 8086 system to have a much larger set of operational instructions and can make calculations to more significant places. Note: the 8085 processor does have two 16-bit registers. The pointer and the program counter.
On 8-bit processors it is 16 bit, but in some processors (MosTek 65xx) the upper eight bit is constant 00000001.
The 8085 has a 16 bit address bus.
The 8085 is an 8-bit microprocessor. Even though there are some 16-bit registers (BC, DE, HL, SP, PC), with some 16-bit operations that can be performed on them, and a 16-bit address bus, the accumulator (A), the arithmetic logic unit (ALU), and the data bus are 8-bits in size, making the 8085 an 8-bit computer.