Sharp MZ As with the standard MZ model, the main unit does not have the system program on onboard
ROM. However, while the old model included only the IPL, a program for controlling advanced hardware is included as an
IOCS and several repairs have been made. One of the functions can call a specific location, so an incompatible element is specified for an application that addresses the module in the ROM and calls it directly without calling the function as a reference.
Two forms of BASIC inserted The instruction set BASIC-S25, which the typical MZ user was familiar with, and the BASIC-M25, which has a
Microsoft-type instruction set that was already at the forefront of the
BASIC environment at that time, was prepared. It is not a conventional model, and Hu-BASIC was adopted in the company's departmental series but has become another implementation of BASIC.
CPU clock improvement The MZ-2500 is equipped with the
Z80A and operates at 4 MHz, but the MZ-2500 is equipped with the Z80B, and except for some, it has 6 MHz operation with one wait during the M1 cycle.
Memory management enhancements While the old model only allowed one to assign a specific address to another space by
bank switching to open a window with text and graphics
VRAM, the MZ-2500 is equipped with a
memory controller, like the MB-S1, etc. It was designed to be able to allocate an arbitrary space in 8 KB units for a memory space divided into eight. This has made it possible to manage 256 KB of main memory and 128 KB of graphics VRAM, and by enabling free allocation, the software can be mapped by mapping video memory in the same arrangement as other models. The porting of the design address space is 512 KB. Various ROMs and RAMs are arranged in this space.
Equipped with Argo Key An Algo function has been added to BASIC due to the aforementioned increase in the degree of freedom of memory mapping and capacity. The Algo function is a key with the mark of the Argo, which is a symbol of the series, that is used as a function to call the built-in application. The "Algo" spelling came from "
algorithm". Close to the resident program, apart from the loaded program, it was possible to start a calculator or the like by key operation as a standard.
Significant enhancement of CRTC In the standard model, the display peripheral which was a specification that the
CPU directly writes to VRAM mapped to the memory space for each plane without having one
ALU has been greatly strengthened in the same machine. The number of colors corresponds to an output of 256 colors in the 320x200 mode and 16 colors in the maximum 640x400 mode. Although not defined as a specification, it is also possible to output at a resolution of 320x400 by installing an additional video memory from the design specification of a custom chip. In addition, simultaneous writing is supported for multiple planes, which enables high-speed drawing even for colors across planes. The palette board has evidence added later in the design and is designed to output specified values in 4096 colors as a palette by interrupting the circuit using a high-speed memory when outputting 16 colors. Also, from the implementation, the existence can not be determined from the software side. In addition to them, having a PCG has made it possible to reduce the definition of external characters as well as the background composition processing in games. In addition to the above display functions, the text screen is a vertically smooth scroll. The graphics screen supports vertical and horizontal smooth scrolling. However, since the 256-color mode is not a packed pixel but an array of stacked planes, the display is not suitable for moving anything. Even in this era, the speed of access to the graphic VRAM itself is not fast because there is no mechanism such as cycle steel. In addition, the execution of the program on the graphic VRAM is not guaranteed, and at the time of read modification write, 2 wait is included.
Loading of kanji text VRAM Like Sharp's
PC-9800 series and
X1turbo, it is equipped with
Kanji text VRAM. It is possible to display the font up to the second
JIS standard only by writing the display code. Processing is much lighter than transferring a font image as a graphic from a kanji ROM, and even though it is an 8-bit machine, it has achieved more comfortable handling of Japanese than models of the same price range.
Data recorder installation Similar to conventional models, a software-controllable
data recorder is attached. The head itself was in stereo, and one channel was available as a data recorder and the other as an audio track. During the late 1980s to early 1990s, the Japanese home computer market shifted to floppy-based software supply, and the tape drive was used only to the extent that some software required a device to play back recorded audio. It was also possible to use it as an answering machine as well as for voice recording. The tape recorder was installed for compatibility with the old model and was removed in the MZ-2520, which is an inexpensive version that does not have the MZ-80B / 2000 mode.
Communication-aware design The MZ-2500 included a serial port and dedicated modem phone socket for "personal computer communication" i.e. to connect to data services online such as
BBSes.[1] Terminal software was also included as standard. The combination of the dedicated devices made it possible to use the built-in data recorder also as an answering machine. ==Hardware==