TI中文支持网PGA970EVM连接USB2ANY进行正弦波数据加载。
利用PGA970GUI,对正弦波发生器进行了设置并按下面的步骤进行了检查，都是正确的。
1. Set the SD bit in the ALPWR register to 0.
2. Set the ADC_EN_VREF bit in the ALPWR register to 1.
3. Turn off the waveform DAC by writing 0 to the WAVE_EN bit in the WAVEFORM_GEN_CTRL register.
4. Load the waveform RAM with quarter-waveform values. For example, to generate a sine wave of amplitude
amp and frequency freq, calculate waveform table values using the formula: amp × sin(2πfreq × (0.5 µs + n1
µs)), n = 0..N. N is the number of 1-µs samples in a quarter-sine wave.
5. Program the N – 1, where N is quarter-waveform table length (value from the previous step) into the
WAVEFORM_TABLE_LEN register .
6. Program the dc bias of the waveform DAC into the WAVEFORM_DAC_OFFSET register. The value is
calculated as: round(DCValue / 1.25 × 16 384). Note that the dc value generated by the waveform generator
should match the waveform gain bias (configuration described as follows).
7. Configure the WAVE_GAIN gain value by writing to the GAIN_CTRL bits in the LVDT_OP_CTRL register.
8. Configure the WAVE_GAIN amplifier for single-ended or differential mode of operation by writing to the SEM
bit in the LVDT_OP_CTRL register.
9. Configure the WAVE_GAIN bias voltage to match the bias value selected in the preceding Step 6 by writing
to the DACVCM_CTRL bits in the LVDT_OP_CTRL register.
10. If WAVE GAIN is configured for differential mode, configure the differential-amplifier output common-mode
voltage by writing to the DIFF_VOCM_CTRL bits in the LVDT_OP_CTRL register.
11. Select either internal or external connection between the PI and PE pins by configuring the SKIP_FILTER bit
inthe LVDT_OP_CTRL register.
12. Connect the waveform DAC to WAVE GAIN by writing 0xF to the TEST_MUX_LVDT_EN bits in the
AMUX_CTRL register.
13. Ensure EN_LB in the LVDT_LPBK_CTRL register is set to 0 to disable loopback.
14. Enable the waveform DAC by writing 1 to WAVE_EN in the WAVEFORM_GEN_CTRL registe
检查了寄存器WAVEFORM-GEN-CTRL正常。
结果就是PI脚正弦波没出来，求助？
user151383853：
直接探测 DAC 的引脚看看
zhi hu：
回复 user151383853:
DAC的输出就是PI引脚吧，我就是测得这个脚
