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| 型号： | AD7280ABSTZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 35/48页 |
| 文件大小： | 0K |
| 描述： | IC BATT MONITOR LI-ION 48LQFP |
| 标准包装： | 1 |
| 功能： | 电池监控器，过压/欠压保护 |
| 电池化学： | 锂离子（Li-Ion） |
| 电源电压： | 8 V ~ 30 V |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 48-LQFP |
| 供应商设备封装： | 48-LQFP（7x7） |
| 包装： | 托盘 |
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AD7280A
WRITE ACKNOWLEDGE
For all write commands received by the AD7280A, the device
internally performs a CRC calculation on Bits[D31:D11] of the
received data and verifies this CRC against the CRC transmitted
by the DSP/microprocessor. If there is a difference between the
CRC generated internally and the CRC received from the DSP/
microprocessor, the AD7280A does not perform the write oper-
ation. The AD7280A also checks for the correct position of the
bit pattern 010 in the write command, as described in the Serial
Interface section. If there is a difference between the expected
010 pattern and the pattern received from the DSP/microprocessor,
the AD7280A does not perform the write operation.
If a subsequent 32 SCLK cycle framed by a CS pulse is applied
to the AD7280A, Bit D10 (the write acknowledge bit) on SDO
indicates to the processor whether the last write to the device
was successful (the write acknowledge bit is set if the write was
successful). The write acknowledge bit is included in the 8-bit
CRC on the read cycle. Note that the read register must be loaded
with any value other than 0x00 for the write acknowledge bit to
be correctly passed down the chain of AD7280A devices.
Following is an example of how the write acknowledge bit can
be used when writing to and configuring a stack of AD7280A
devices. This example sets the high byte of the control register
settings on all devices in a stack of eight AD7280As.
For example, to read back the write acknowledge bit from
Device 1 in the chain after writing to a register on that device,
the read operation of Device 0, the master device, must be turned
off. Also, the SCLK frequency must be lower than 1 MHz when
reading back the write acknowledge bit from devices higher in
the chain than the master device in this mode.
CYCLIC REDUNDANCY CHECK
The AD7280A 32-bit SPI interface includes an 8-bit cyclic
redundancy check (CRC) on the read and write cycles. The CRC
can be used to detect alterations in the data during transmission
to and from the AD7280A. The principle of a cyclic redundancy
check is that the data to be transmitted is divided by a fixed poly-
nomial. The remainder of this mathematical operation is then
attached to the data and forms part of the transmission. At the
receiving end, the same mathematical operation should be com-
pleted on the data received. This operation confirms that the
data received is the same as the data that was originally transmitted.
The polynomial used by the AD7280A to calculate the CRC bits
is x 8 + x 5 + x 3 + x 2 + x + 1. This CRC polynomial has a Hamming
distance of 4 for calculations up to 22 bits of data. The division
Write Operation CRC
For writes to the AD7280A, the CRC must be computed in the
DSP/microprocessor and sent as part of the write command.
1.
2.
3.
Execute a write all command to load the read register with
0x0E (addresses the low byte of the control register).
Execute a write all command to set the high byte of the
control register (Address 0x0D) to the desired values.
Apply an additional eight sets of 32 SCLKs, each framed by
The CRC must be computed on Bits[D31:D11] of the write
command, that is, the device address, the register address, the
data to be written, the address all parts bit, and Bit D11, which
is a reserved zero input bit. The data is divided by the CRC
polynomial, and the 8-bit remainder, following the division,
CS, to the master device. The device address bits, D31 to
D27, should be set to 0x1F for each 32 SCLK frame. The
32-bit write command is 0xF800030A. The data read back
from the master device on the first 32 SCLK frame includes
the write acknowledge bit for the control register high byte
write to the master device. The data read back on the
second 32 SCLK frame includes the write acknowledge bit
for the control register high byte write to the first slave
device in the stack, and so on.
To read back the write acknowledge bit from slave AD7280As
in a daisy chain when single registers are being written to,
Bits[D13:D12] of the control register on lower devices in the
chain must be set to 1 (a no-read operation on those devices).
becomes the CRC bits, CRC_7 to CRC_0.
If the user is addressing all parts in a stack of AD7280As (by
asserting the address all parts bit, D12), the CRC must be com-
puted using a device address of 0x00, and the data written to the
device must have a device address of 0x00. The AD7280A performs
the same CRC calculation on Bits[D31:D11] of the received data,
and it verifies this CRC against the CRC transmitted by the DSP/
microprocessor. If there is a difference between the CRC gener-
ated within the AD7280A and the CRC received from the DSP/
microprocessor, the AD7280A does not perform the write opera-
tion. To allow the user to verify that the command has been
received and implemented by the AD7280As in the stack, a
write acknowledge bit is also included in the 32-bit read cycles.
For more information about the write acknowledge bit, see the
Write Acknowledge section.
DATA_IN
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
D
Q
CRC_0
CRC_1
CRC_2
CRC_3
CRC_4
CRC_5
CRC_6
CRC_7
SCLK
Figure 40. CRC Implementation
Rev. 0 | Page 35 of 48
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7280ABSTZ-RL | 功能描述:IC BATTERY MONITOR LI-ION 48LQFP RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
| AD7280AWBSTZ | 功能描述:IC BATT MON LI-ION AUTO 48LQFP RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
| AD7280AWBSTZ-RL | 功能描述:IC BATT MON LI-ION AUTO 48LQFP RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
| AD7280BSTZ | 制造商:Analog Devices 功能描述: |
| AD7280BSTZ-RL | 制造商:Analog Devices 功能描述: |
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