The Zilog eZ80
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What is the Zilog eZ80 ?
https://en.wikipedia.org/wiki/Zilog_eZ80
“The Zilog eZ80 is an 8-bit microprocessor from Zilog, introduced in 2001. eZ80 is an updated version of the company’s first product, the Z80 microprocessor“
Why use the Zilog eZ80…
digikey.co.uk
eZ80 Registers
What is wrong with an ARM ?
Microprocessors no longer exist…
Systems-on-a-Chip (“SoC”)
What is an SoC ?
A “System on a Chip”” is an integrated circuit (also known as a “chip”) that integrates all or most components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memory, input/output ports and secondary storage, often alongside other components such as radio modems and a graphics processing unit (GPU) – all on a single substrate or microchip. It may contain digital, analog, mixed-signal, and often radio frequency signal processing functions (otherwise it is considered only an application processor)
Microprocessors DO still exist… !!
Z80’s for “legacy designs”
Endianness
“Endianness is the order or sequence of bytes of a word of digital data in computer memory. Endianness is primarily expressed as big-endian (BE) or little-endian (LE). A big-endian system stores the most significant byte of a word at the smallest memory address and the least significant byte at the largest. A little-endian system, in contrast, stores the least-significant byte at the smallest address” Source: Wikipedia
Image#1: The Nature of Endianness Source: Wikipedia#1 Wikipedia#2
In the image above, the example is of a unsigned 32-bit integer (shown as hex), but it is equally valid for 16-bit values. The (e)Z80 is “Little-endian”