Hi All,
I am evaluating CC3200 launchpad, Now working on ADC (Pin 58 of CC3200 launchpad). As per my previous experince that offset value should be fixed in any hardware. Here I have modify code( ADC example code from SDK of CC3200) as per below:
1. extract ADC value (12-bits) from 32-bit of total data.
2. convert it into mV range.
3. averaging of acquired 4096 samples.
4. and sending it on Teraterm.
I have got below report in which ADC data is near but offset value is changing.
| ADC PIN 58 Testing dt: 31/12/2014 | ||||||||||
| Instruments: | TI CC3200 Launchpad, Lenovo Laptop, CCS v6 free liecense, Tektronix make Programmable Power Supply PWS4323 | |||||||||
| Software Detail: | OSPL ADC v1 | |||||||||
| Teraterm Output: | Teraterm Output 31_12_2014.docx | |||||||||
| Sr.No. | Input Voltage (mV) | Measured Voltage (mV) | ||||||||
| 1 | 50 | mV | 69 | mV | ||||||
| 2 | 100 | mV | 128 | mV | ||||||
| 3 | 150 | mV | 188 | mV | ||||||
| 4 | 200 | mV | 247 | mV | ||||||
| 5 | 250 | mV | 309 | mV | ||||||
| 6 | 300 | mV | 370 | mV | ||||||
| 7 | 350 | mV | 431 | mV | ||||||
| 8 | 400 | mV | 492 | mV | ||||||
| 9 | 450 | mV | 554 | mV | ||||||
| 10 | 500 | mV | 615 | mV | ||||||
| 11 | 550 | mV | 676 | mV | ||||||
| 12 | 600 | mV | 737 | mV | ||||||
| 13 | 650 | mV | 798 | mV | ||||||
| 14 | 700 | mV | 859 | mV | ||||||
| 15 | 750 | mV | 921 | mV | ||||||
| 16 | 800 | mV | 982 | mV | ||||||
| 17 | 850 | mV | 1043 | mV | ||||||
| 18 | 900 | mV | 1105 | mV | ||||||
| 19 | 950 | mV | 1167 | mV | ||||||
| 20 | 1000 | mV | 1226 | mV | ||||||
| 21 | 1050 | mV | 1289 | mV | ||||||
| 22 | 1100 | mV | 1350 | mV | ||||||
| 23 | 1150 | mV | 1411 | mV | ||||||
| 24 | 1200 | mV | 1471 | mV | ||||||
Please help/guide me If I am going in wrong direction.
Thanks & regards
Bhavdipsinh Rathod