schematic

Press RESET immediately, All! I corrected one error, previously there were 2 bits mixed up: === Cut === The proposed modification can be easily carried out on computers KAY, PENTAGON, SCORPION and others not assembled on PLM. It allows you to use the spectrum memory much more efficiently, than just through one 16kb page in the address space of the processor. The number of pages has been increased to four and they cover all 64kb of memory addressed to Z80. Any memory bank within the first 256kb can be included in any processor memory window. The rest of the memory is addressed as before. Within the first 256kb programs can be located operating with large volumes of data and frequently used data. in memory more than 256kb can accommodate programs content a 16kb code and data segment (for example, device drivers) or disk cache, Ramdisk... Maybe 256kb is not enough, I don’t know if it’s worth complicating the scheme too much? All of these computers with RAM capacity of 128kb and above have port 7FFD controls switching memory pages in the window with address C000. The circuit design of the memory manager in different computers is small What is the difference: there is a port decoder, a 555TM9 register and a multiplexer 555KP11. The presence of the 555KP11 microcircuit makes it easy to implement finalized, often only 1 microcircuit may be required.You will need to disconnect pin 15 of the 555KP11 microcircuit from the board, it will used to switch modes. You also need a control port configuration (for example, in Scorpio or Kai you can use 1FFD, only 1 bit will be needed, set when resetting to 0 and never not installed in 1 TR-DOS programs. You will also need one inverter. SCHEME: D47 is a 555KP11 computer memory manager chip SCORPION, "yellow board". For other computers you need according to the scheme clarify the correspondence between the contacts of the 555KP11 microcircuit and the signals D0, D1, D2, D4 data buses. D48 pin 9 -- write signal to port 7FFD on the “yellow scorpion”, available on all computers on pin 9 microcircuits 555TM9... SPECTRUM BUS ┌──┬──────┐ connects to D47 D4 >──────15──┤D0│ RG │ output: D2 >───────1──┤D1│ Q0├─10───> 12 D0 >───────2──┤D2│ Q1├─9────> 9 D1 >───────3──┤D3│ Q2├─7────> 7 ├──┤ Q3├─6────> 4 A10 >──────14──┤W0│ │ A11 >──────13──┤W1│ │ wr7FFD >──────12──┤WR│ │ (D48/9) ├──┤ │ A14 >───────5──┤R0│ │ A15 >───────4──┤R1│ │ ┌──11──┤OE│ │ │ └──┴──────┘ │ 555ИР26 │ └──────────────────┐ │ switching on ┌──┐ │ ext. >──────┬───────┤1 o────┘ addressing │ └──┘ according to log. 1 │ ЛH1 └────────────────> D47 pin 15 (CS) !!!! There must also be some way to turn off the ROM!!! This is done differently on different computers. How will the extended addressing mode be enabled? And I don’t specifically write to turn off the ROM. On different machines this is can be done or has already been done in different ways. PROGRAMMING VIA PORTS ┌──────────┬────────────┬────── ─────┬───────────┬────────────┐ │ PORT │ 73FD │ 77FD │ 7BFD │ 7FFD │ ├──────────┼────────────┼────── ─────┼───────────┼────────────┤ │ BITS │ │ │ │ │ │ 0 │ R0-0000 │ R0-4000 │ R0-8000 │ R0-C000 │ │ │ │ │ │ │ │ 1 │ R1-0000 │ R1-4000 │ R1-8000 │ R1-C000 │ │ │ │ │ │ │ │ 2 │ R2-0000 │ R2-4000 │ R2-8000 │ R2-C000 │ │ │ │ │ │ ││ 3 │ screen 5/7 │ screen 5/7 │ screen 5/7 │ screen 5/7 │ │ │ │ │ │ │ │ 4 │ R3-0000 │ R3-4000 │ R3-8000 │ R3-C000 │ │ │ │ │ │ │ │ 5 │ LOCK │ LOCK │ LOCK │ LOCK │ │ │ │ │ │ │ │ * 6 │ R3-C000 │ R3-C000 │ R3-C000 │ R3-C000 │ │ │ │ │ │ │ │ ** 7 │ R4-C000 │ R4-C000 │ R4-C000 │ R4-C000 │ │ │ │ │ │ │ └──────────┴────────────┴────── ─────┴───────────┴────────────┘ * Bit 6 is only used in PENTAGON computers with the capacity RAM more than 128kb ** Bit 7 is used only in KAY or PENTAGON computers with more than 256kb of RAM. The number of the addressed memory bank is calculated using the formula: n ___ \n /__ (Rx)*(2^x) ; n=2..8 (depending on the type of computer). x=0 ( 128..8192kb ) Setting the LOCK bit to 1 locks the 7xFD ports for writing. Ports 73FD, 77FD, 7BFD, 7FFD are used to install recorded they contain a memory bank at addresses 0000, 4000, 8000, C000, respectively. The selected ports are decrypted identically in all commonSoviet clones of ZX-SPECTRUM as a port of 7FFD. All possible conflicts are associated only with switching to the extended mode, which on different on computers can be implemented in different ways. In most cases, modification is useless for TR-DOS programs. The benefits will be enormous when used in the operating system which can distribute memory between different programs or parts of the program, it also becomes possible to implement real multitasking with programs of real (>64kb) size, but again, you need an appropriate operating system, but not tape recorder emulator. If something is unclear or you have suggestions, write: Kirill Frolov 2:5030/827.2@fidonet.org 2:5030/946.25@fidonet.org 500:812/1.507@zxnet 500:812/23.25@zxnet P.S.: Everything is already done and working. Buy 555IR26 on the radio market in St. Petersburg problem. === Cut === *Crossposted in REAL.SPECCY * Crossposted in ZX.SPECTRUM

Hello, volton What I had - I threw it in your mail! - on volton#tut.by

Hello, All I'm looking for an electrical circuit diagram of a computer byte 48... Maybe someone has it in electronic form...