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Where does the ROM go on a Z80?
Since the Z80 starts executing code at address 0 when it first turns out, our ROM has to be located at address 0. The Z80 has a 16-bit address meaning that it can access a maximum of 64KB memory, and thus to keep things simple, we will divide our memory in half with the first being ROM and the second being RAM.
What kind of memory does the Z80 have?
The Z80 has a 16-bit address meaning that it can access a maximum of 64KB memory, and thus to keep things simple, we will divide our memory in half with the first being ROM and the second being RAM. Thus, our ROM will be 32KB with an address range between 0 and 16383 while RAM will range between 16834 to 65536.
Can a Z80 CPU read data from address Ax?
As soon as OE goes low, the data found at address Ax will appear on the data pins and can be read by any digital logic circuit including the Z80 CPU and microcontrollers. To write data to address Ax But how do we connect a memory IC to a Z80 CPU? What circuitry do we need to make to get the reading and writing to work?
How is bankbaseadr used in Z80 memory mapping?
The BankBaseAdr is the address range that is used for comparison with the Z80 CPU address bits. It is masked by the BankMask which determines the number of bits which should be used. It is a constant value and is also known for a given builds.
What can I do with a Z80 address?
The first task is to decode the Z80 address so that, depending on the value of the address, a specific device can be selected with its own chip select line. To do this, we use a 4515, which is a demultiplexer that converts a 4-bit input into a 16-wire output.
What are the registers on a Z80 CPU?
The Z80, despite being an 8-bit CPU, has some 16-bit instructions, which use 8-bit pair registers. These register pairs are BC, DE, and HL. Other useful registers also include the flag register (F, which holds information such as carry, negative, and overflow), and the index registers I, X, and Y.