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参数资料
| 型号： | IS82C37A |
| 厂商： | Harris Corporation |
| 英文描述： | CMOS High Performance Programmable DMA Controller |
| 中文描述： | 高性能的CMOS可编程DMA控制器 |
| 文件页数： | 10/23页 |
| 文件大小： | 204K |
| 代理商： | IS82C37A |
4-201
82C37A
Mask Register -
Each channel has associated with it a mask
bit which can be set to disable an incoming DREQ. Each
mask bit is set when its associated channel produces anEOP
if the channel is not programmed to Autoinitialize. Each bit of
the 4-bit Mask register may also be set or cleared separately
or simultaneously under software control. The entire register
is also set by a Reset or Master clear. This disables all hard-
ware DMA requests until a Clear Mask Register instruction
allows them to occur. The instruction to separately set or clear
the mask bits is similar in form to that used with the Request
register. Refer to the following diagram and Figure 4 for
details. When reading the Mask register, bits 4-7 will always
read as logical ones, and bits 0-3 will display the mask bits of
channels 0-3, respectively. The 4 bits of the Mask register
may be cleared simultaneously by using the Clear Mask Reg-
ister command (see software commands section).
Mask Register
All four bits of the Mask register may also be written with a
single command.
Status Register -
The Status register is available to be read
out of the 82C37A by the microprocessor. It contains
information about the status of the devices at this point. This
information includes which channels have reached a terminal
count and which channels have pending DMA requests. Bits
0-3 are set every time a TC is reached by that channel or an
external EOP is applied. These bits are cleared upon RESET,
Master Clear, and on each Status Read. Bits 4-7 are set
whenever their corresponding channel is requesting service,
regardless of the mask bit state. If the mask bits are set, soft-
ware can poll the Status register to determine which channels
have DREQs, and selectively clear a mask bit, thus allowing
user defined service priority. Status bits 4-7 are updated while
the clock is high, and latched on the falling edge. Status Bits
4-7 are cleared upon RESET or Master Clear.
Temporary Register -
The Temporary register is used to
hold data during memory-to-memory transfers. Following the
completion of the transfers, the last byte moved can be read
by the microprocessor. The Temporary register always
contains the last byte transferred in the previous memory-to-
memory operation, unless cleared by a Reset or Master
Clear.
7
6
5
4
3
2
1
0
BIT NUMBER
00
01
10
11
Select Channel 0 mask bit
Select Channel 1 mask bit
Select Channel 2 mask bit
Select Channel 3 mask bit
0
1
Clear mask bit
Set mask bit
7
6
5
4
3
2
1
0
BIT NUMBER
0
1
Clear Channel 0 mask bit
Set Channel 0 mask bit
0
1
Clear Channel 1 mask bit
Set Channel 1 mask bit
0
1
Clear Channel 2 mask bit
Set Channel 2 mask bit
0
1
Clear Channel 3 mask bit
Set Channel 3 mask bit
Don’t Care
Don’t Care,
Write
All Ones,
Read
Status Register
7
6
5
4
3
2
1
0
BIT NUMBER
1
Channel 0 has reached TC
1
Channel 1 has reached TC
1
Channel 2 has reached TC
1
Channel 3 has reached TC
1
Channel 0 request
1
Channel 1 request
1
Channel 2 request
1
Channel 3 request
OPERATION
A3
A2
A1
A0
IOR
IOW
Read Status Register
Write Command Register
Read Request Register
Write Request Register
Read Command Register
Write Single Mask Bit
Read Mode Register
Write Mode Register
Set First/Last F/F
Clear First/Last F/F
Read Temporary Register
Master Clear
Clear Mode Reg. Counter
Clear Mask Register
Read All Mask Bits
Write All Mask Bits
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
FIGURE 4. SOFTWARE COMMAND CODES AND REGISTER CODES
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相关代理商/技术参数 |
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| IS82C37A-12 | 制造商:HARRIS 制造商全称:HARRIS 功能描述:CMOS High Performance Programmable DMA Controller |
| IS82C37A-5 | 功能描述:外围驱动器与原件 - PCI DMA CONTROLLER IC -4 0+85C 5.0V 5.0MHZ DM RoHS:否 制造商:PLX Technology 工作电源电压: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:FCBGA-1156 封装:Tray |
| IS82C50A | 制造商:未知厂家 制造商全称:未知厂家 功能描述:UART |
| IS82C50A-5 | 功能描述:UART 接口集成电路 PERIPH UART/BRG 5V 10MHZ 44PLCC IND RoHS:否 制造商:Texas Instruments 通道数量:2 数据速率:3 Mbps 电源电压-最大:3.6 V 电源电压-最小:2.7 V 电源电流:20 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:LQFP-48 封装:Reel |
| IS82C50A-5Z | 功能描述:UART 接口集成电路 W/ANNEAL PERIPH UART /BRG 5V 10MHZ RoHS:否 制造商:Texas Instruments 通道数量:2 数据速率:3 Mbps 电源电压-最大:3.6 V 电源电压-最小:2.7 V 电源电流:20 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:LQFP-48 封装:Reel |
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