TI中文支持网现在用cc2530F256开发产品发现一个问题，就是通过下面函数获得芯片的工作电压，但是发现，随着温度的降低，监测的电压也随着变小，实际的供电电压是没有改变的，
static uint8 readVoltage(void)
{
uint16 value;
// Clear ADC interrupt flag ADCIF = 0;
ADCCON3 = (0x00 | 0x10 | 0x0f);
// Wait for the conversion to finish while ( !ADCIF );
// Get the result
value = ADCL;
value |= ((uint16) ADCH) << 8;
// value now contains measurement of Vdd/3
// 0 indicates 0V and 32767 indicates 1.25V
// voltage = (value*3*1.25)/32767 volts
// we will multiply by this by 10 to allow units of 0.1 volts
value = value >> 6; // divide first by 2^6
value = (uint16)(value * 34.5);
value = value >> 9; // …and later by 2^9…to prevent overflow during multiplication
return value;
}
Susan Yang：
您现在是使用电池供电的？ 建议尝试以下操作
定义
#define HAL_ADC_EOC 0x80 // End of Conversion bit#define HAL_ADC_START 0x40 // Starts Conversion#define HAL_ADC_RESOLUTION_8 0x01#define HAL_ADC_RESOLUTION_10 0x02#define HAL_ADC_RESOLUTION_12 0x03#define HAL_ADC_RESOLUTION_14 0x04#define HAL_ADC_CHN_VDD3 0x0f // VDD/3#define HAL_ADC_REF_125V 0x00 // Internal Reference (1.15V for CC2530)
调用函数 uint16 sampledVoltage = adcRead( HAL_ADC_CHN_VDD3, HAL_ADC_RESOLUTION_12 );
使用 adcRead()uint16 adcRead (uint8 channel, uint8 resolution)
{
int16 reading = 0;
uint8 i, resbits;
uint8 adcChannel = 1;
if (channel < 8)
for (i=0; i < channel; i++)
adcChannel <<= 1;
/* Enable channel */
ADCCFG |= adcChannel;
/* Convert resolution to decimation rate */
switch (resolution) {
case HAL_ADC_RESOLUTION_8:
resbits = HAL_ADC_DEC_064;
break;
case HAL_ADC_RESOLUTION_10:
resbits = HAL_ADC_DEC_128;
break;
case HAL_ADC_RESOLUTION_12:
resbits = HAL_ADC_DEC_256;
break;
case HAL_ADC_RESOLUTION_14:
default:
resbits = HAL_ADC_DEC_512;
break;
}
/* writing to this register starts the extra conversion */
ADCCON3 = channel | resbits | HAL_ADC_REF_125V;
/* Wait for the conversion to be done */
while (!(ADCCON1 & HAL_ADC_EOC));
/* Disable channel after done conversion */
ADCCFG &= (adcChannel ^ 0xFF);
/* Read the result */
reading = (int16) (ADCL);
reading |= (int16) (ADCH << 8);
/* Treat small negative as 0 */
if (reading < 0)
reading = 0;
switch (resolution) {
case HAL_ADC_RESOLUTION_8:
reading >>= 8;
break;
case HAL_ADC_RESOLUTION_10:
reading >>= 6;
break;
case HAL_ADC_RESOLUTION_12:
reading >>= 4;
break;
case HAL_ADC_RESOLUTION_14:
default:
reading >>= 2;
break;
}
return ((uint16)reading);
}
shaojun jiang：
回复 Susan Yang:
你好，测试了，还是不行，-20度，电压偏差有0.2v左右，常温下读值正确，温度低了就有偏差了
user4484888：
回复 shaojun jiang:
你好，你的问题解决了吗？
user4484888：
回复 Susan Yang:
你好 在吗
我也遇到类似低温的时候，产品工作不正常。
YiKai Chen：
回复 user4484888:
不同溫度條件下的ADC讀值需要自行校正
Susan Yang：
回复 user4484888:
请您将问题详细描述后重新发帖，请不要跟踪旧贴，谢谢
