參數(shù)資料
型號(hào)： AM53CF94JC
廠商： ADVANCED MICRO DEVICES INC
元件分類： 總線控制器
英文描述： Enhanced SCSI-2 Controller (ESC)
中文描述： SCSI BUS CONTROLLER, PQCC84
封裝： PLASTIC, LCC-84
文件頁(yè)數(shù)： 17/76頁(yè)
文件大小： 735K
代理商： AM53CF94JC
P R E L I M I N A R Y
AMD
17
Am53CF94/Am53CF96
Current Transfer Count Register
(00H, 01H, 0EH) Read Only
Current Transfer Count Register
CTCREG
Address: 00
H,
01
H, 0EH
Type: Read
15
14
13
12
11
10
9
8
CRVL15
CRVL14
CRVL13 CRVL12 CRVL11 CRVL10
CRVL9
CRVL8
x
x
x
x
x
x
x
x
7
6
5
4
3
2
1
0
CRVL7
CRVL6
CRVL5
CRVL4
CRVL3
CRVL2
CRVL1
CRVL0
x
x
x
x
x
x
x
x
23
22
21
20
19
18
17
16
CRVL23
CRVL22
CRVL21
CRVL20 CRVL19
CRVL18
CRVL17
CRVL16
x
x
x
x
x
x
x
x
17348B-16
CTCREG – Bits 23:0 – CRVL 23:0 – Current
Value 23:0
This is a three-byte register which decrements to keep
track of the number of bytes transferred during a DMA
transfer. Reading these registers returns the current
value of the counter. The counter will decrement by one
for every byte and by two for every word transferred. The
transaction is complete when the count reaches zero,
and bit 4 of the Status Register (04H) is set. Should the
sequence terminate early, the sum of the values in the
Current FIFO (07H) and the Current Transfer Count
Register reflect the number of bytes remaining.
The least significant byte is located at address 00H, the
middle byte is located at address 01H, and the most sig-
nificant byte is located at address 0EH.
Register 0EH
extends the total width of the register from 16 to 24
bits, and is only enabled when the Enable Features
bit (bit 6) of Control Register Two is set to a value
of ‘1’.
These registers are automatically loaded with the val-
ues in the Start Transfer Count Register every time a
DMA command is issued. However, following a chip or
power on reset, up until the time register 0EH is loaded,
the Am53CF94/96’s part-unique ID can be obtained by
reading register 0EH.
In the Target mode, this counter is decremented by the
active edge of
DACK
during the Data-In phase and by
REQC
during the Data-Out phase.
In the Initiator mode, the counter is decremented by the
active edge of
DACK
during the Synchronous Data-In
phase or by
ACKC
during the Asynchronous Data-In
phase and by
DACK
during the Data-Out phase.
Start Transfer Count Register
(00H, 01H, 0EH) Write Only
Start Transfer Count Register
STCREG
Address: 00
H–
01
H
Type: Write
15
14
13
12
11
10
9
8
STVL15
STVL14
STVL13
STVL12
STVL11
STVL10
STVL9
STVL8
x
x
x
x
x
x
x
x
7
6
5
4
3
2
1
0
STVL7
STVL6
STVL5
STVL4
STVL3
STVL2
STVL1
STVL0
x
x
x
x
x
x
x
x
23
22
21
20
19
18
17
16
STVL23
STVL22
STVL21
STVL20 STVL19
STVL18
STVL17 STVL16
x
x
x
x
x
x
x
x
17348B-17
STCREG – Bits 15:0 – STVL 15:0 – Start Value 15:0
This is a three-byte register which contains the number
of bytes to be transferred during a DMA operation. The
value in the Start Transfer Count Register must be pro-
grammed prior to command execution.
The least significant byte is located at address 00H, the
middle byte is located at address 01H, and the most sig-
nificant byte is located at address 0EH. Register 0EH
extends the total width of the register from 16 to 24 bits,
and is only enabled when the Enable Features bit (bit 6)
of Control Register Two is set to a value of ‘1’. This sets
the maximum transfer count to 16.78 MBytes. When a
value of ‘0’ is written to these registers, the transfer
count will be set to the maximum. A DMA NOP com-
mand must be issued before the transfer counter values
can be written to 00H, 01H, and 0EH.
These registers retain their value until overwritten, and
are therefore unaffected by a hardware or software re-
set. This reduces programming redundancy since it is
no longer necessary to reprogram the count for subse-
quent DMA transfers of the same size.
相關(guān)PDF資料
PDF描述
Am53CF94JCW Enhanced SCSI-2 Controller (ESC)
Am53CF94KC Enhanced SCSI-2 Controller (ESC)
Am53CF94KCW Enhanced SCSI-2 Controller (ESC)
Am53CF96 Enhanced SCSI-2 Controller (ESC)
Am53CF96JC Enhanced SCSI-2 Controller (ESC)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AM53CF94JCW 制造商:AMD 制造商全稱:Advanced Micro Devices 功能描述:Enhanced SCSI-2 Controller (ESC)
AM53CF94KC 制造商:AMD 制造商全稱:Advanced Micro Devices 功能描述:Enhanced SCSI-2 Controller (ESC)
AM53CF94KCW 制造商:AMD 制造商全稱:Advanced Micro Devices 功能描述:Enhanced SCSI-2 Controller (ESC)
AM53CF96 制造商:AMD 制造商全稱:Advanced Micro Devices 功能描述:Enhanced SCSI-2 Controller (ESC)
AM53CF96JC 制造商:AMD 制造商全稱:Advanced Micro Devices 功能描述:Enhanced SCSI-2 Controller (ESC)
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