The ADS8684 and ADS8688 are 4- and 8-channel, integrated data acquisition systems based on a 16-bit successive approximation (SAR) analog-to-digital converter (ADC), operating at a throughput of 500 kSPS. The devices feature integrated analog front-end circuitry for each input channel with overvoltage protection up to ±20 V, a 4- or 8-channel multiplexer with automatic and manual scanning modes, and an on-chip, 4.096-V reference with low temperature drift. Operating on a single 5-V analog supply, each input channel on the devices can support true bipolar input ranges of ±10.24 V, ±5.12 V, and ±2.56 V, as well as unipolar input ranges of 0 V to 10.24 V and 0 V to 5.12 V. The gain of the analog front-end for all input ranges is accurately trimmed to ensure a high dc precision. The input range selection is software-programmable and independent for each channel. The devices offer a 1-MΩ constant resistive input impedance irrespective of the selected input range.
The ADS8684 and ADS8688 offer a simple SPI-compatible serial interface to the digital host and also support daisy-chaining of multiple devices. The digital supply operates from 1.65 V to 5.25 V, enabling direct interface to a wide range of host controllers.
ADS8688主要特性:
16-Bit ADC with Integrated Analog Front-End
4-, 8-Channel MUX with Auto and Manual Scan
Channel-Independent Programmable Input Ranges:
Bipolar: ±10.24 V, ±5.12 V, and ±2.56 V
Unipolar: 0 V to 10.24 V and 0 V to 5.12 V
5-V Analog Supply: 1.65-V to 5-V I/O Supply
Constant Resistive Input Impedance: 1 MΩ
Input Overvoltage Protection: Up to ±20 V
On-Chip, 4.096-V Reference with Low Drift
Excellent Performance:
500-kSPS Aggregate Throughput
DNL: ±0.5 LSBINL: ±0.75 LSB
Low Drift for Gain Error and Offset
SNR: 92 dBTHD: –102 dB
Low Power: 65 mW
AUX Input → Direct Connection to ADC Inputs
SPI™-Compatible Interface with Daisy-Chain
–40℃ to 125℃ Industrial Temperature Range
TSSOP-38 Package (9.7 mm × 4.4 mm)
图1. ADS8688功能框图
图2. 用于电源自动化的ADS8688八路复用数据采集系统框图
图3. 用于PLC的ADS8688 16位八路综合模拟输出模块框图
ADS8688EVM-PDK 评估模块
The ADS8688EVM-PDK is a platform for evaluating the ADS8688 device. The ADS8688EVM-PDK consists of an ADS8688EVM board and an SDCC controller card. The SDCC is an FPGA-based controller card that functions as an serial peripheral interface (SPI™) host and transfers data to the ADS8688EVM graphical user interface (GUI) via a USB interface. The ADS8688EVM GUI collects, analyzes, and records data from the ADS8688EVM board. The ADS8688EVM GUI is capable of collecting data from the ADS8688EVM in auto and manual modes, configuring the ADC program registers, and performing FFT analysis of data captured from the ADC.
ADS8688EVM-PDK 评估模块主要特性:
• Includes support circuitry as a design example to match ADC performance.
• 3.3-V slave SPI.
• Serial interface header for easy connection to the SDCC controller card.
• Designed for a 5-V analog supply.
• Integrated 4.096-V voltage reference.
• Bipolar (±10.24 V, ±5,12 V, ±2.56 V )or unipolar(0 V to 10.24 V, 0 V to 5.12 V) input ranges for each channel.
• Onboard, second-order, Butterworth, low-pass filters for four channels.
• Onboard regulator for generating a ±15-V bipolar supply for second-order, Butterworth, low-pass filters.
• Capable of accepting a ±100-mV signal on the negative analog inputs (AIN_xGND).
ADS8688EVM-PDK 评估模块GUI特性:
• Captures data from the ADS8688EVM in auto and manual modes.
• Configures the ADS8688 device program registers.
• Enables and disables channels in auto mode.
• FFT analysis and calculates the SNR, THD, and SINAD ac performance parameters.
• Single and multiple graph views for captured data.
• Includes a dc histogram for dc inputs.
• Logs ADC data.
图4.ADS8688EVM-PDK 评估模块外形图: microSD存储卡和SDCC控制板
The ADS8688EVM-PDK includes microSD memory cards that contain the EVM software and SDCC controller board firmware required for the EVM operation
你好，ADS8344是一个ADC转换器，8路梁轮输入，8位串行控制输入，16位串行数据输出。下面是写的程序，粘到记事本里看，百度敬渣枯上显得乱。
/* ADS8344 */
#define uchar unsigned char
#define uword unsigned int
sbit ADS_SHDN =
sbit ADS_CS =
sbit ADS_DCLK =
sbit ADS_DIN =
sbit ADS_BUSY =
sbit ADS_DOUT =
// (MSB) (LSB)
// BIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
// SA2 A1 A0 —SGL/DIF PD1 PD0
void ads_com(uchar ads_comchar)
{
uchar i=0
for (i=8i>0i--)
{
ADS_DIN = ads_comchar&0x80//取最高位
ADS_DCLK = 0
ADS_DCLK = 1
ads_comchar<<=1//左移数据
}
}
// (MSB)(LSB)
// BIT15 ...... BIT0
uword ads_dat(void)
{
uword ads_datword = 0
uchar i=0
for (i=16i>0i--)
{
ads_datword<<=1//左移数据
ADS_DCLK = 0
if(DOUT==1) ads_datword = ads_datword|0x01/亮洞/最低位或
ADS_DCLK = 1
}
return(ads_datword)
}
void main()
{
uword ADS_DataWord = 0
ADS_SHDN = 1
ADS_CS = 1
ADS_DCLK = 0
ADS_CS = 0
// SA2 A1 A0 —SGL/DIF PD1 PD0
// 1000— 1 11
ads_com(0x87)//10000111
ADS_DCLK = 0
ADS_DCLK = 1
while(ADS_BUSY == 1)
ADS_DataWord = ads_dat()
ADS_CS = 1
while(1)
}
我不是神人，但我希望可以帮你解决问题，呵呵……首先，我有个小问题，你要求算的是2+4+8+……+100,是不是2的1次方，2次方，3次方？如果是，那应该是2+4+8+16+32+64，怎么有还加100呢？或者你笔误，应该是2—100之间的偶数相加呢？
好，下面来解决你的问题:
1.用ADS1.2运行你的加法程序，要注意一点就是ADS不能直链接运行C遍出来的程序，要用汇编代码启动。下面是启动代码startup.s文件（我空间有关于这个代码的分析，你可以去看看）：
IMPORT |Image$$RO$$Limit|
IMPORT |Image$$RW$$Base|
IMPORT |Image$$ZI$$Base|
IMPORT |Image$$ZI$$Limit|
IMPORT Main 声明C程序中的Main()函数
AREA Start,CODE,READONLY 声明代码段Start
ENTRY标识程序入口
CODE32声明32位ARM指令
Reset LDR SP,=0x40003F00
初始化C程序的运行环境
LDR R0,=|Image$$RO$$Limit|
LDR R1,=|Image$$RW$$Base|
LDR R3,=|Image$$ZI$$Base|
CMP R0,R1
BEQ LOOP1
LOOP0 CMP R1,R3
LDRCC R2,[R0],#4
STRCC R2,[R1],#4
BCC LOOP0
LOOP1 LDR R1,=|Image$$ZI$$Limit|
MOV R2,#0
LOOP2 CMP R3,R1
STRCC R2,[R3],#4
BCC LOOP2
B Main 跳转到C程序代判差码Main()函数
END
2. 启动代码写好后，再编写C代码，运行你的程序（按你的意思算）
#define uint8 unsigned char //这两个宏定义是ADS里面防止数据溢迹冲好出带的
#define uint32 unsigned int
#define N 100
uint32 sum
// 使用加法运算来计算2+4+8+……+N的值。
void Main(void)
{ uint32 i
sum = 0
for(i=0i<=Ni=i*2)
{ sum += i
}
while(1)
}
3. 这两个程序合在一起才是是完整的ADS实现程序，希望可以解决你的困惑。姿铅
祝你进步！
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