PC8477BV-1 National Semiconductor, PC8477BV-1 Datasheet - Page 28

• Manufacturer Part Number: PC8477BV-1
• Description: IC ADVANCED FLOPPY CTRLR 68PLCC
• Manufacturer: National Semiconductor
• Series: SuperFDC™r

Specifications of PC8477BV-1

• Controller Type: Floppy Disk Controller
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 68-LCC (J-Lead)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Supply: -
• Interface: -
• Other names: *PC8477BV-1

4 0 Command Set Description
4 2 19 Set Track Command
This command is used to inspect or change the value of the
internal Present Track Register This could be useful for re-
covery from disk mis-tracking errors where the real current
track could be read through the Read ID command and
then the Set Track command could be used to set the inter-
nal Present Track Register to the correct value
If the WNR bit is a 0 a track register is to be read In this
case the Result Phase byte contains the value in the inter-
nal register specified and the third byte in the Command
Phase is a dummy byte
If the WNR bit is a 1 data is written to a track register In this
case the third byte of the Command Phase is written to the
specified internal track register and the Result Phase byte
contains this new value written
The DS1 and DS0 bits select the Present Track Register for
the particular drive The internal register address depends
on MSB DS1 and DS0 as shown in Table 4-12 This com-
mand does not generate an interrupt
4 2 20 Specify Command
The Specify command sets the initial values for three inter-
nal timers The function of these Specify parameters is de-
scribed below The parameters of this command are unde-
fined after power up and are unaffected by any reset Thus
software should always issue a Specify command as part of
an initialization routine This command does not generate
an interrupt
The Motor Off and Motor On timers are artifacts of the
drive motor until a read or write operation is started and the
delay of deselecting the drive motor after the command is
completed Since the PC8477B enables the drive and motor
select line directly through the DOR these timers only pro-
vide some delay from the initiation of a command until it is
actually started
Step Rate Time These four bits define the time interval
between successive step pulses during a seek implied
seek recalibrate or relative seek The programming of this
step rate is shown in Table 4-13
PD765 These timers determine the delay from selecting a
Data Rate
500 kb s
300 kb s
250 kb s
DS1
0
0
0
0
1
1
1
1
1 Mb s
TABLE 4-13 Step Rate Time (SRT) Values
TABLE 4-12 Set Track Register Address
DS0
0
0
1
1
0
0
1
1
(16-SRT) x 0 5
(16-SRT)
(16-SRT) x 1 67
(16-SRT) x 2
Value
MSB
0
1
0
1
0
1
0
1
Register Addressed
0 5–8
1–16
1 67–26 7
2–32
Range
PTR0(LSB)
PTR0(MSB)
PTR1(LSB)
PTR1(MSB)
PTR2(LSB)
PTR2(MSB)
PTR3(LSB)
PTR3(MSB)
(Continued)
Units
ms
ms
ms
ms
28
Motor Off Time These four bits determine the simulated
Motor Off time as shown in Table 4-14
Note MFT
Motor On Time These seven bits determine the simulated
Motor On time as shown in Table 4-15
Note 1 MNT
Note 2 For PC8477A at 500 kb s when TMR
DMA This bit selects the data transfer mode in the Execu-
tion Phase of a read write or scan operation
4 2 21 Verify Command
The Verify command reads logical sectors containing a Nor-
mal Data AM from the selected drive without transferring
the data to the host This command is identical to the Read
Data command except that no data is transferred during
the Execution Phase
The Verify command is designed for post-format or post-
write verification Data is read from the disk as the control-
ler checks for valid Address Marks in the Address and Data
Fields The CRC is computed and checked against the pre-
viously stored value on the disk The EOT value should be
set to the final sector to be checked on each side If EOT is
greater than the number of sectors per side the command
will terminate with an error and no useful Address Mark or
CRC data will be given
The TC pin cannot be used to terminate this command
since no data is transferred The command can simulate a
TC by setting the EC bit to a 1 In this case the command
will terminate when SC (Sector Count) sectors have been
read (If SC
0 then the command will terminate when EOT is equal to
the last sector to be checked In this case the Data Length
parameter should be set to FF hex Refer to Table 4-7 for
the Result Phase values for a successful completion of the
command Also see Table 4-16 for further explanation of
the result bytes with respect to the MT and EC bits
500 kb s MFT x 16
300 kb s MFT x 80 3 26 7 – 427 MFT x 2560 3 853 –13653
250 kb s MFT x 32
500 kb s
300 kb s MNT x 10 3 3 3–427 MNT x 160 3 53–6827
250 kb s
1 Mb s
Data
Rate
1 Mb s MFT x 8
Data
Rate
0
1
range is 2–256
TABLE 4-14 Motor Off Time (MFT) Values
TABLE 4-15 Motor On Time (MNT) Values
DMA mode is selected
Non-DMA mode is selected
e
Mode 1 (TMR
Mode 1 (TMR
MNT x 4
e
0 is treated as Motor Off Time
Value
e
Value
MNT
MNT
0 is treated as Motor On Time
0 then 256 sectors will be verified ) If EC
8 – 128
16 –256
32 –512
Range
Range
1–128
1–128
4–512
e
e
0)
0)
MFT x 512
MFT x 512
MFT x 1024
MNT x 32
MNT x 32
MNT x 64
Mode 2 (TMR
Value
Mode 2 (TMR
Value
e
e
e
16
0 the value is MNT x 2 and
128
512 –8192
512 –8192
1024 – 16384 ms
32–4096
32–4096
64–8192
Range
Range
e
e
1)
1)
Units
Units
ms
ms
ms
ms
ms
ms
ms
e