Sinclair Town #02 31 декабря 1994

Железо

Iron - Encore Controller KP1818VG93 the floppy drive. Block diagram of the controller floppy disk drive. The instruction set of the microcontroller.

 Suchkov, Oleg, 95.


   LSI CONTROLLER KR1818VG93

   Flexible disk unit


  IC KR1818VG93 a single-chip
programmable device,
designed to control
information output from the mainframe to
floppy disks and output
information from a floppy disk into the computer. BIS
provides programming
track number, sector and side of the disc, as well as the 
length of the sector, the search modes tracks and install a 
magnetic head (mg) original position, read / write mode of 
information transfer rate of MG. VG93 allows you to organize 
automatic control reads and writes information on the control 
code (CC), recorded at the end of the index and data arrays. 
Indexed array includes an address tag,

sector number, the length of the sector,
The track number and the number of
disc. Data set contains a label directly
data. In the recording mode chip provides delivery 
precompensation signal recording, depending on the codes that 
represent information. Output information from a computer 
running on a signal Query data formed chip, and read is 
determined by the ready signal and Momentum Index, issued by 
the instrumental logic of the floppy disk drive. 

   Technical data and features chip KR1818VG93
with Ucc = 5V and 12V and currents of consumption of 60 and 20 
mA: 

Load capacity of exits,
pF to 100
Maximum power consumption
Power, MW, less than 500


   Record information on GMI is carried out with single or 
double density. Under the single density means account 
information with frequency modulation shown in figure 1




   Under the double-density recording of information refers to 
the modified modulation (Fig. 2).



   Chip designed to work with GMD of 3.5 '5.25'.
Maximum number of programmable
tracks on the KMT - 256. Maximum speed of information exchange 
in a single recording density is 250 kbit / s, double density 
recording - 500 Kbps. Clock frequency of external oscillator is 
1 MHz for GMD 5.25 '. Chip implemented

in 40-pin package. Conclusions
33, 38, 39 chips - the conclusions of
open source, requiring
connection to power supply
Uss through the resistor 10
ohms.



   BLOCK DIAGRAM FDD CONTROLLER


   Block diagram of the controller floppy disk
shown in Fig. 3. Sharing information with MP occurs at the 
8-bit data bus DB0-DB7 through Data Buffer (DB). Interface with

MP (IMP) provides creation of control signals for transferring 
data and control information. 

********************************

   To simplify the printing unit
- The scheme and its study, it is given in
text file format IS-DOS
in the root directory of the disc. File BSKD.
********************************


   Input signal CS (choice
chips) permits operation
Products with the MP. Inputs R (reading) and W (write) provide
read and write information from the MP
8-bit internal register
controller, which number is determined by the information on 
the inputs A0, A1.


   Appointment of internal registers LSI, selected by address 
signals A0, A1, the following:


   Data register (RGD) is used for data storage
during read and write operations to disk. When executing the 
"Search" RD stores the desired track.


   Shift register (RgSD) takes input from RAWR if
clock input RCLK
read from the disk serial data and transmits the received byte 
in the RD. When recording to CD RNC receives information from

RD and provides data through BUD at
Output WD.

   Register sector (RgSK) - used to store information about
room reading or writing sector.

   Register paths (RgDR) is
to record numbers to the desired track or store information 
about track number, which is MG. He increases his

value of 1 when moving to the MG
lane 79, and decreases it when
Traffic MG to the track 00.

   Command register (RgKom) stores
code executes the command and can not be loaded a new team
not yet completed execution
the previous one.

   Status register (RgSost)
remembers the current state of
various functional units
chips and floppy disk drive. The functional purpose of each bit 
RgSost when the appropriate commands given in Table. 2. 
Indicated (signs corresponds to the "Log. 1"

RgSost). Access to registers is determined on the lines of code
A0, A1:
 at 01 - read and write DDR
 at 10 - RSK
 at 11 - RD.
 At 00 to the write operation is set RK, and on the operation
Reading - PCT.


   Registers, tracks, sectors and
Data are bidirectional. Register allocation in
address space of external
Device ZX Spectrum shown
Figure 4.



   In the disk interface is
one feature connected with
shadow position ROM. Unfortunately this also applies to the 
registers of the microcontroller. Their addresses appear in the 
address space only at the time of the disk system. From BASIC

- The system registers nedostupny.
Not provided access to them
from the ROM disk system.

   Detector address labels (DAME)
determines the index address
marker (IAM) and the address label
data for reading and
write to the disk.

   Shaper control
Code (CFC) is used to
control or regeneration cycle control code (CC).

   Arithmetic - logical node
(ALU) contains the serial
comparator circuit and add
subtracting 1, and is used for
modification of registers and comparison with the field 
identifier stored on disk. 

   The control unit (CU)
generates signals nobhodimye
for internal control blocks of the chip.

   The control unit disc (BUD)
generates the signals necessary
to manage the disk and
movement of MG.



COMMAND SYSTEM microcontroller.


   Chip picks
and the implementation of 11 teams. All teams divided into four 
types (Table 3).: 


   - Auxiliary

   - Writing and reading information

   - Search and read the index

     field at the KMT

   - Forced break

     Dependence of Change
     MG absorption of codes n1, H0, and

     state input

     TEST.


   Assigning commands Products:


    The restore command allows the transition to the zero MG
Track GMD. If the input TR00
there is no evidence of withdrawal on
zero track after the issuance of 256
pulses, the command
terminated.


    Search command assumes,
RgDor that contains information about
current track number and the Hopf -
desired track. Movement
MG holds up until
RgDor content is equal to the
Content RGD. The search is performed at V = 1.


    STEP command provides for the pulse on the movement of MG
one step. Permeschenie direction is not changed.


    Teams step forward and provide STEP BACK give a warning 
signal DIRC (the direction of movement).



   Type 2 teams provide
reading of information from the KMT
(Fig. 4) and write it on the KMT. Before entering these 
commands need to set the number of RgSekt the desired sector. 
The length of the sector given the code and is written in the 
index field for formatting the drive in accordance with the 
information below (Table 4):