HOLTEK HT6576A

HT6576A
Advanced SCSI CHIP
Features
•
•
•
•
•
Support the ANSI X3.131-1986 standard
Asynchronous transfer rate to 5 Mbyte/sec
Support initiator and target mode
0.8um CMOS process
•
•
On chip 48mA single-ended drivers and
receivers
Non internal clock needed
44pins PLCC package
Block Diagram
1
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HT6576A
Pin Diagram
Pin Description
Host Interface Signal
Pin No
Pin Name
I/O
Description
14~16
A0~A2
I
Address Lines
17
CS
I
Chip Select, active low
11
DACK
I
DMA Acknowledge, active low
9
DRQ
O
DMA Request
24~28,
20~22
D0~D7
10
EOP
I
End of Process, active low
19
IOR
I
I/O Read, active low
18
IOW
I
I/O Write, active low
8
IRQ
O
Interrupt Request
13
READY
O
Ready
7
RESET
I
Reset, active low
I/O
Data Lines
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HT6576A
SCSI Interface Signals
Pin No
Pin Name
I/O
Description
33
ACK
I/O
Acknowledge, active low
6
ATN
I/O
Attention, active low
4
BSY
I/O
Busy, active low
30
C/D
I/O
Control/Data, active low
32
I/O
I/O
Input/Output, active low
29
MSG
I/O
Message, active low
34
REQ
I/O
Request, active low
2
RST
I/O
Reset, active low
37~41,
43, 44, 1
DB0–DB7
I/O
SCSI Data Bus, active low
35
DBP
I/O
SCSI Parity Bit, active low
5
SEL
I/O
Select, active low
VSS
3, 12, 31, 36, 42
VDD
23
Registers
Address 0
Current SCSI data register(READ ONLY)
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB2
DB1
DB0
The SCSI bus parity is checked at the beginning of the read cycle.
Output data register(WRITE ONLY)
DB7
DB6
DB5
DB4
DB3
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HT6576A
Address 1: Initiator command register
WRITE
7
6
5
ASSERT
TRI–STATE RESERVED
RST
4
3
2
1
0
ASSERT
ACK
ASSERT
BSY
ASSERT
SEL
ASSERT
ATN
ASSERT
DATA
• BIT 7: ASSERT RST
WHEN SET, THE RST SIGNAL IS ASSERTED ON THE SCSI BUS
• BIT 6: TRI–STATE (TEST MODE)
• BIT 5: RESERVED (0)
• BIT 4: ASSERT ACK
WHEN SET, THE ACK SIGNAL IS ASSERTED ON THE SCSI BUS
• BIT 3: ASSERT BSY
WHEN SET, THE BSY SIGNAL IS ASSERTED ON THE SCSI BUS
• BIT 2: ASSERT SEL
WHEN SET, THE SEL SIGNAL IS ASSERTED ON THE SCSI BUS
• BIT 1: ASSERT ATN
WHEN SET, THE ATN SIGNAL IS ASSERTED ON THE SCSI BUS
• BIT 0: ASSERT DATA
WHEN SET, This bit allows the contents of the output data register to be enabled as chip outputs
on SCSI signal DB0–DB7
READ
7
6
5
4
3
2
1
0
RET
ARBIT
PROGRESS
LOST
ARBIT
ACK
BSY
SEL
ATN
ASSERT
DATA
Address 2: Mode register
READ/WRITE
7
6
5
4
3
2
1
0
LOCK
DMA
TARGET
MODE
ENABLE
PARITY
ENABLE
PARITY
ENABLE
EOP
MONITOR
CHECK
BUSY
DMA
IRQ
MODE
ARBIT
• BIT 7: BLOCK MODE DMA
• BIT 6: TARGET MODE
When set, the chip operates as an SCSI bus target device.
• BIT 5: ENABLE PARITY CHECKING
When set, data received on the SCSI data bus is checked for odd parity.
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HT6576A
• BIT 4: ENABLE PARITY INTERRUPT
When set, this bit causes the IRQ signal to be asserted if a parity error is detected.
• BIT 3: ENABLE EOP INTERRUPT
When set, this bit causes the IRQ signal to be asserted if EOP is received from the DMA controller.
• BIT 2: MONITOR BUSY
When set, this bit causes the IRQ signa asserted when BSY changes to the inactive state for at
least a bus settle delay.
• BIT 1: DMA MODE
• BIT 0: Arbitrate
When set, this bit starts the arbitration process.
Address 3: Target command register
7
6
5
4
3
2
1
0
LAST BYTE
X
X
X
ASSERT
REQ
ASSERT
MSG
ASSERT
C/D
ASSERT
I/O
R
R/W
R/W
R/W
R/W
• BIT 7: LAST BYTE SEND (READ ONLY)
• BIT 3: ASSERT REQ
WHEN SET, THE REQ SIGNAL IS ASSERTED ON THE SCSI BUS (IN TARGET MODE)
• BIT 2: ASSERT MSG
WHEN SET, THE MSG SIGNAL IS ASSERTED ON THE SCSI BUS (IN TARGET MODE)
• BIT 1: ASSERT C/D
WHEN SET, THE C/D SIGNAL IS ASSERTED ON THE SCSI BUS (IN TARGET MODE)
• BIT 0: ASSERT I/O
WHEN SET, THE I/O SIGNAL IS ASSERTED ON THE SCSI BUS (IN TAGRTE MODE)
Address 4: Current SCSI Bus Register
READ
7
6
5
4
3
2
1
0
RST
BSY
REQ
MSG
C/D
I/O
SEL
DBP
WRITE
–SELECT ENABLE REGISTER
7
6
5
4
3
2
1
0
SID7
SID6
SID5
SID4
SID3
SID2
SID1
SID0
5
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HT6576A
Address 5: Bus And Status
READ
7
6
END
DMA
WRITE
5
DMA
REQUEST
4
PARITY
ERROR
3
IRQ
2
PHASE
MATCH
1
BUS ERROR
0
ATN
ACK
–START DMA SEND
7
6
5
4
3
2
1
0
X
X
X
X
X
X
X
X
Address 6: Input Data
READ
7
6
5
4
3
2
1
0
LDB7
LDB6
LDB5
LDB4
LDB3
LDB2
LDB1
LDB0
LATCH SCSI DATA. The register represent the complement of the active low SCSI data bus.
WRITE
–START DMA TARGET RECEIVE
7
6
5
4
3
2
1
0
X
X
X
X
X
X
X
X
Address 7:
READ
–RESET PARITY/INTERRUPT
7
6
5
4
3
2
1
0
X
X
X
X
X
X
X
X
WRITE
–START DMA INITIATOR RECEIVE
7
6
5
4
3
2
1
0
X
X
X
X
X
X
X
X
6
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HT6576A
Interrupts
SELECTION/RESELECTION
• SEL= ACTIVE LOW
• BSY IS FALSE FOR AT LEAST 400NS
• HT6576A DEVICE ID (SELECT REGISTER) is active on the SCSI bus will generate IRQ.
END OF PROCESS (EOP) INTERRUPT
• EOP= ACTIVE LOW
• DACK= ACTIVE LOW
• IOR OR IOW= ACTIVE LOW
• DMA MODE
• ENABLE EOP IRQ⇒ GENERATE EOP IRQ
SCSI BUS RST/IRQ
When An SCSI RST active low, the IRQ is generated.
PARITY ERROR IRQ
An IRQ is generated for a received parity error if enable parity checking bit and the enable
parity interrupt bit are set.
BUS PHASE MISMATCH IRQ
If the DMA MODE bit is active and a phase mismatch occurs when REQ from false to true,
an interrupt is generated
LOSS OF BSY/IRQ
• MONITOR BSY bit= 1
• BSY= ACTIVE LOW FOR 400ns WILL GENERATE IRQ
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HT6576A
Electrical Characteristics
D.C. Characteristics
(Ta=25°C)
Absolute Maximum Ratings
Symbol
Parameter
Min.
Max.
Unit
Tstg
Storage Temperature
–55
150
°C
VDD
Supply Voltage
–0.5
7.0
V
VIN
Input Voltage
VSS–0.5
VDD+0.5
V
ESD
Electrostatic Discharge
–5000
5000
V
(Ta=25°C)
Operating Conditions
Symbol
Parameter
Min.
Max.
Unit
VDD
Supply Voltage
4.75
5.25
V
IDD
Supply Current
—
20
mA
Ta
Operating Free-Air
0
70
°C
(Ta=25°C)
SCSI Signals
Symbol
Characteristic
Condition
Min.
Max.
Unit
VIH
Input High Voltage
—
2.0
VDD+0.5
V
VIL
Input Low Voltage
—
VSS–0.5
0.8
V
VOL
Output Low Voltage
IOL=48mA
VSS
0.5
V
VHYS
Hysteresis
—
200
450
mV
IOL
Output Low Current
VOL=0.5
48
—
mA
IIH
Input High Leakage
VIH= 5.25V
—
50
µA
IIL
Input Low Leakage
VIL=VSS
—
–50
µA
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HT6576A
(Ta=25°C)
Microprocessor Data Bus D0-D7
Symbol
Characteristic
Condition
Min.
Max.
Unit
VIH
Input High Voltage
—
2.0
VDD+0.5
V
VIL
Input Low Voltage
—
VSS–0.5
0.8
V
VOH
Output High Voltage
IOH=–4.0mA
2.4
VDD
V
VOL
Output Low Voltage
IOL=8.0mA
VSS
0.4
V
IOH
Output High Current
VOH=VDD–0.5V
–4.0
—
mA
IOL
Output Low Current
VOL=0.4V
8.0
—
mA
IIH
Input High Leakage
VIH=5.25V
—
10
µA
IIL
Input Low Leakage
VIL=VSS
—
–10
µA
ITL
Tri-State Leakage
–10
10
µA
—
(Ta=25°C)
A0~A2, CS, EOP, IOR, IOW, RESET
Symbol
Characteristic
Condition
Min.
Max.
Unit
VIH
Input High Voltage
—
2.0
VDD+0.5
V
VIL
Input Low Voltage
—
VSS–0.5
0.8
V
IIH
Input High Leakage
VIH=5.25V
10
—
µA
IIL
Input Low Leakage
VIL=VSS
–10
—
µA
Min.
Max.
Unit
DRQ, IRQ, READY,
Symbol
Characteristic
Condition
VOH
Output High Voltage
IOH=–4.0mA
2.4
VDD
V
VOL
Output Low Voltage
IOL=8.0mA
VSS
0.4
V
IOH
Output High Current
VOH=VDD–0.5V
–4.0
—
mA
IOL
Output Low Current
VOL=0.4V
8.0
—
mA
9
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HT6576A
Timing Diagram
Initiator Send
Name
Description
Min.
Max.
Unit
t1
SCSI Data setup time to ACK active
40
—
ns
t2
Data Bus held time from IOW inactive
10
—
ns
t3
IOW active time
30
—
ns
t4
DACK active, to DRQ inactive
—
20
ns
t5
ACK active to next DRQ active
—
45
ns
t6
EOP active time
30
—
ns
10
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HT6576A
Initiator Receive
Name
Description
Min.
Max.
Unit
t1
IOR inactive to next REQ active
50
—
ns
t2
REQ active to ACK active
50
—
ns
t3
IOR inactive to ACK inactive
10
—
ns
t4
ACK inactive time
50
—
ns
t5
Data Bus hold time from IOR inactive
10
—
ns
t6
Data Bus valid time from IOR active
—
20
ns
t7
REQ active to DRQ active
—
25
ns
t8
DACK active to DRQ inactive
—
20
ns
t9
DACK inactive to next DRQ active
20
—
ns
t10
EOP active time
30
—
ns
11
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HT6576A
Target Send (Non-block mode)
Name
Description
Min.
Max.
Unit
t1
SCSI data hold time from IOW inactive
—
30
ns
t2
SCSI data setup time to REQ active
40
—
ns
t3
ACK active to REQ inactive
—
30
ns
t4
Data Bus setup time to IOW inactive
10
—
ns
t5
Data Bus hold time from IOW inactive
10
—
ns
t6
IOW active time
30
—
ns
t7
DACK active to DRQ inactive
—
20
ns
t8
IOW inactive to DACK inactive
0
—
ns
t9
ACK active to next DRQ active
—
45
ns
12
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HT6576A
Target Receive (Non-block mode)
Name
Description
Min.
Max.
Unit
t1
ACK inactive to next REQ active
50
—
ns
t2
ACK active to REQ inactive
—
30
ns
t3
IOR inactive to next REQ active
50
—
ns
t4
Data Bus setup time to IOR active
—
20
ns
t5
Data Bus hold time from IOR inactive
10
—
ns
t6
IOR active time
30
—
ns
t7
DACK active to DRQ inactive
—
20
ns
t8
IOR inactive to DACK inactive
0
—
ns
13
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HT6576A
PIO Timing
t1
t3
t2
t2
D7~0
A2~0
CS
IOR
t4
t4
IOW
RESET
DACK
DRQ
Name
Description
Min.
Max.
Unit
t1
Data valid time from IOR active
—
20
ns
t2
Data hold time from IOR inactive
10
—
ns
t3
Data setup time to IOW inactive
10
—
ns
t4
IOR or IOW active time
30
—
ns
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