On-Line #80 30 апреля 1996

ATM Turbo

System - Personal computer ATM TURBO 2 +: Technical Description and Programmer's Guide: System port multiplexer pages.

                 SYSTEM


(C) MicroArt
(C) MaxSoft 1995

          Personal computer TURBO 2 +
             PCB version 7.00-7.10
       Technical Description and Programmer's Guide.

           The structure of memory and I / O ports.


            1. System port

            Address Access: # 77
           Picks: A0 = 1, A1 = 1, A2 = 1, A3 = 0, A4 = 1, A7 = 
0, WR = 0 

   Appeal to this port will be implemented in dosen = on or
from the regime of CP / M.

D0 - RG0 \
D1 - RG1 - code videomode
D2 - RG2 /
D3 - TUR frequency processor 1-7MHz 0-3.5MHz
D4 - Z_M reserved - must be set to 0
D5 - Z_I interrupts HSYNC (50 Hz), 1-allowed 0 - disabled
D6 - VE1 1-interdiction operation 8031 ​​(all requests go to 
the zx        keyboard)

D7 - VE0 the board as 7.10 is not used (default is necessary
     set to 1)

A8 - PEN 0 - off. memory manager (system ROM included
     in all windows), 1 - incl. memory manager.

A9 - CPM 0 - inclusion dosen write permission to the port
      pages, SYS ets. 1 - lock dosen (entry ports
      sys, pgwr, fdd, hdd only from TR-DOS)

A14-PEN2 0 - recording resolution panel, 1-ban entry panel

; Screen video modes RG2'RG1'RG0
; Sinclair 3
; 640x200 GRAPH 2
; 320x200 GRAPH 0
; 640x200 Text 6


   Programmers need to remember that when you switch from
Sinclair mode screen and high resolution screens, entangled 
address space of RAM namely A5, A6, A7 and A8, A9, A10 
respectively, ie if you want to switch the display mode - 
switching program should take no longer than 32 bytes and 
located at identical with A5, A6, A7 and A8, A9, A10, 
respectively, otherwise your program will hang! 


               2. Multiplexer pages

            Access address: # F7
           Picks: A0 = 1, A1 = 1, A2 = 1, A3 = 0, A4 = 1, A7 = 
1, WR = 0 


   Appeal to this port will be implemented in dosen-active
or from the regime of CPM. Application Manager has allowed to 
address in PC RAM and up to 1024KB 1024KB ROM. In this case, it 
is possible to include _LYUBUYU_ page of memory (16KB) in 
_LYUBOE_ of the four windows memory (address: # 0000, # 4000, # 
8000, # C000) at 16K. Manager is divided into two parts of 4 
bytes each. These parts contain a map of pages in ROM2 = 0 and 
ROM2 = 1. 

D0 - RAM'ROM invert PAGE 0;
D1 - RAM'ROM invert PAGE 1 \
D2 - RAM'ROM invert PAGE 2 \ inverse number of the page
D3 - RAM'ROM invert PAGE 3 /
D4 - RAM'ROM invert PAGE 4 /
D5 - RAM'ROM invert PAGE 5 /
D6 - RAM / ROM 1-resolution RAM ,0-ROM
D7 - MX_A 1 to allow signaling (PAGE0-PAGE2) from the port
      # 7FFD

A14 - window sel 0; sampling window 0 - # 0000 1 - # 4000 2 - # 
8000 A15 - window sel 1 / 3 - # C000




   Standard map of the distribution of memory in different modes
the computer:


mode Spectrum-128 Spectrum-1948 TR-DOS CPM-system CPM-users
roms ROM2 = 1 ROM2 = 0 ROM2 = x ROM2 = 1 ROM2 = 0

# 0000 ROM-# 3E ROM-# 3C ROM-# 3D ROM-# 3F RAM-0
# 4000 5 RAM-RAM-5 RAM-5 RAM-RAM-May 4
# 8000 RAM-2 RAM-2 RAM-2 RAM-2 RAM-2
# C000, see the state of port # 7FFD RAM-1 or 3 RAM-3


In the ZX-SPECTRUM in the window with the address # C000 may be 
included Any page with a 0 to 7 (depending on the STATUS port # 
7FFD) 

CPM-system-mode when active ROM monitor (work with standard 
procedures for screening of Mr. I / O drives, optical grew 
keyboard interrupt) 

CPM-users-active mode when the user program
        (Box 0 - Page 0 RAM)


   Note for fans to use all the RAM in the 1024K
SPECTRUM mode.

Below is a standard procedure for switching pages in 1024
K for SPECTRUM.

 When you call in the A page number is 0-3FH (it must be 
remembered that  stack and the calling program should not be 
located at the addresses above  # C000)


SET_PAGE:
    PUSH AF
    AND 7; distinguish the younger 3-bit
    OR # 10, at the discretion can select ROM and the screen.
    LD BC, # 7FFD
    OUT (C), A
    POP AF
    AND # 38; mask the all the bits except the 3 senior
    CPL; data inversion
               ; (Bit sample RAM platoon)
    LD BC, # 2A53; in TR-DOS - OUT (C), A RET
    PUSH BC
    LD BC, # FFF7
    JP # 3D2F; transition in TR-DOS

After any such command port # 7FFD off.

If you want to correctly return to the SPECTRUM mode - run:

EXIT_1024:
    LD A, # FF
    LD BC, # 2A53
    PUSH BC
    LD BC, # FFF7
    JP # 3D2F
further management pages as usual on port # 7FFD



And it's not all ... Continued in the next room.