gm82c765b ETC-unknow, gm82c765b Datasheet - Page 12

• Manufacturer Part Number: gm82c765b
• Description: Floppy Disk Subsystem Controller
• Manufacturer: ETC-unknow

Fig 2. TYPICAL GM 82C765B APPLICATION SYSTEM
trig-ger receivers and can be hooked up to a bus
or backplane without any additional buffering.
main status Register must be ready by the
processor before each byte of information is
written into or read from the data Register. After
each byte of data is read from or written into the
data Register, the CPU should wait for 12uS
before reading the main status Register. Bits D6
and D7 in the main status Register must be in a 0
and 1 state, respectively, before each byte of the
command word may be written into the
GM82C765B. Many of the command require
multiple bytes. As a result, the Main status
Register must be read prior to each byte transfer
to the GM82C765B. During the result phase,
Inputs, except the data bus, are Schmitt
During the command or result phases, the
MICROPROCESSOR
INTERFACE
ADDRESS
RECODE
CLOCK
MAIN
CKTS
BUS
CKT
GND
GND
VCC
VCC
V
CC
=+5V
1 RD
2. WR
16 IRQ
19 RST
15 DMA
4 A0
5 DACK
40 VCC
7-14 DB0-DB7
6 TC
3 CS
17
18
22 DRV
24 PCVAL
23
21
LDOR
CLK1
LDCR
CLK2
GM82C765B
RWC
DS
DS
12
3
4
* DCHG
Bits D6 and D7 in the Main status Register must
both be 1’s (D6-1 and D7-1) before reading
each byte from the Data Register. Note that this
regarding of the main status Register before
each byte transfer to the GM82C765B is
re-quired only in the Command and result phases,
and not during the Execution phase. Note also
that DB6 and DB7 in the MSR can be polled
in-stead of waiting 12uS. When they have the
right bit settings, the GM82C765B is ready for
com-mands. This might save some time.
register need not be read.
is in the non-DMA Mode, then the receipt of
each data byte is indicated by an interrupt signal
on pin 16 (IRQ-1). The generation of a Read
signal (RD-0) will clear the interrupt as well as
TROO
DIRC
MO
RPM
MO
HDL
RDD
STEP
DS
DS
WD
WE
IDX
WP
VSS 31
HS
2
1
2
During the Execution phase, the main status
1
33
36
35
30
32
34
26
29
28
25
27
20
37
39
36
40
150
150
150
150
150
* PLCC version of
CONNECTOR
INTERFACE
GM82C765B
FLOPPY
DRIVE
DISK
If the GM82C765B
GM82C765B