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ADuC7020BCPZ62I-RL 参数 Datasheet PDF下载

ADuC7020BCPZ62I-RL图片预览
型号: ADuC7020BCPZ62I-RL
PDF下载: 下载PDF文件 查看货源
内容描述: 精密模拟微控制器, 12位模拟I / O , ARM7TDMI MCU [Precision Analog Microcontroller, 12-Bit Analog I/O, ARM7TDMI MCU]
分类和应用: 微控制器和处理器外围集成电路时钟
文件页数/大小: 104 页 / 1747 K
品牌: ADI [ ADI ]
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ADuC7019/20/21/22/24/25/26/27/28/29  
Data Sheet  
ADCCP = 0x10; // Select Temperature  
Sensor as an // input to the ADC  
Table 28. VCM Ranges  
AVDD VREF  
VCM Min VCM Max Signal Peak-to-Peak  
REFCON = 0x01; // connect internal 2.5V  
reference // to Vref pin  
3.3 V 2.5 V  
1.25 V  
2.05 V  
2.276 V  
2.55 V  
1.75 V  
1.976 V  
2.25 V  
2.5 V  
2.048 V 1.024 V  
2.048 V  
1.25 V  
2.5 V  
2.048 V  
1.25 V  
ADCCON = 0xE4; // continuous conversion  
1.25 V  
0.75 V  
1.25 V  
while(1)  
{
3.0 V 2.5 V  
2.048 V 1.024 V  
while (!ADCSTA){};  
// wait for end of conversion  
1.25 V  
0.75 V  
CALIBRATION  
b = (ADCDAT >> 16);  
By default, the factory-set values written to the ADC offset  
(ADCOF) and gain coefficient registers (ADCGN) yield  
optimum performance in terms of end-point errors and  
linearity for standalone operation of the part (see the  
Specifications section). If system calibration is required, it is  
possible to modify the default offset and gain coefficients to  
improve end-point errors, but note that any modification to the  
factory-set ADCOF and ADCGN values can degrade ADC  
linearity performance.  
// To calculate temperature in °C, use  
the formula:  
a = 0x525 - b;  
// ((Temperature = 0x525 - Sensor  
Voltage) / 1.3)  
a /= 1.3;  
b = floor(a);  
printf("Temperature: %d  
oC\n",b);  
For system offset error correction, the ADC channel input stage  
must be tied to AGND. A continuous software ADC conversion  
loop must be implemented by modifying the value in ADCOF until  
the ADC result (ADCDAT) reads Code 0 to Code 1. If the  
ADCDAT value is greater than 1, ADCOF should be decremented  
until ADCDAT reads 0 to 1. Offset error correction is done  
digitally and has a resolution of 0.25 LSB and a range of  
}
return 0;  
}
BAND GAP REFERENCE  
Each ADuC7019/20/21/22/24/25/26/27/28/29 provides an on-  
chip band gap reference of 2.5 V, which can be used for the ADC  
and DAC. This internal reference also appears on the VREF pin.  
When using the internal reference, a 0.47 µF capacitor must be  
connected from the external VREF pin to AGND to ensure stability  
and fast response during ADC conversions. This reference can  
also be connected to an external pin (VREF) and used as a refer-  
ence for other circuits in the system. An external buffer is required  
because of the low drive capability of the VREF output. A program-  
mable option also allows an external reference input on the VREF  
pin. Note that it is not possible to disable the internal reference.  
Therefore, the external reference source must be capable of  
overdriving the internal reference source.  
3.125% of VREF  
.
For system gain error correction, the ADC channel input stage  
must be tied to VREF. A continuous software ADC conversion  
loop must be implemented to modify the value in ADCGN  
until the ADC result (ADCDAT) reads Code 4094 to Code 4095.  
If the ADCDAT value is less than 4094, ADCGN should be  
incremented until ADCDAT reads 4094 to 4095. Similar to the  
offset calibration, the gain calibration resolution is 0.25 LSB  
with a range of 3% of VREF  
.
TEMPERATURE SENSOR  
The ADuC7019/20/21/22/24/25/26/27/28/29 provide voltage  
output from on-chip band gap references proportional to  
absolute temperature. This voltage output can also be routed  
through the front-end ADC multiplexer (effectively an additional  
ADC channel input) facilitating an internal temperature sensor  
channel, measuring die temperature to an accuracy of ±3°C.  
Table 29. REFCON Register  
Name  
Address  
Default Value  
Access  
REFCON  
0xFFFF048C  
0x00  
R/W  
The band gap reference interface consists of an 8-bit MMR  
REFCON, described in Table 30.  
The following is an example routine showing how to use the  
internal temperature sensor:  
Table 30. REFCON MMR Bit Designations  
Bit  
7:1  
0
Description  
int main(void)  
{
Reserved.  
Internal reference output enable. Set by user to  
connect the internal 2.5 V reference to the VREF pin.  
The reference can be used for an external component  
but must be buffered. Cleared by user to disconnect  
the reference from the VREF pin.  
float a = 0;  
short b;  
ADCCON = 0x20;  
delay(2000);  
// power-on the ADC  
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