Hi Suraj,
Q1: I'm keeping EN_BUCK to 0V for now but what should be its value ideally?
Ideally, the EN_BUCK should be floating if the buck is enabled. The 22uH inductor should be connected.
Q2: Also I'm writting 3-phase command to SPI with register value of 0x1008 and when I read it for the first time I get 0x1008 as return value which is I believe correct for 3-pwm mode. But when I try to read same register again then I just get 0x1400 as return value. Why is 0x1008 overwritten automatically if that's what happened?
Q3: Sometimes SPI just returns 0x0000 or i.e. doesn't return anything and in that case I keep reading with the same command then with tries of 2 or 3 I get success. Why is SPI communication unreliable?
The SPI transactions should be reliable. Noise could be affecting the operation. Please provide scope captures of the SPI transactions with all 4 signals.
Q4: Even when I do not apply PWM and EN_BUCK=0V then there is by default a PWM signal of 3.3V at the GX_X pins of DRV8301. When I apply PWM at INX_X pins I get output very noisy PWM (not rectangular in shape but shape like that of capacitor charging) of 5V only, how do I increase this output voltage of PWM to say 8V??
Can you provide a scope capture of the GX_x outputs with and without a PWM?
Q1: I'm keeping EN_BUCK to 0V for now but what should be its value ideally?
Ideally, the EN_BUCK should be floating if the buck is enabled. The 22uH inductor should be connected.
Q2: Also I'm writting 3-phase command to SPI with register value of 0x1008 and when I read it for the first time I get 0x1008 as return value which is I believe correct for 3-pwm mode. But when I try to read same register again then I just get 0x1400 as return value. Why is 0x1008 overwritten automatically if that's what happened?
Q3: Sometimes SPI just returns 0x0000 or i.e. doesn't return anything and in that case I keep reading with the same command then with tries of 2 or 3 I get success. Why is SPI communication unreliable?
The SPI transactions should be reliable. Noise could be affecting the operation. Please provide scope captures of the SPI transactions with all 4 signals.
Q4: Even when I do not apply PWM and EN_BUCK=0V then there is by default a PWM signal of 3.3V at the GX_X pins of DRV8301. When I apply PWM at INX_X pins I get output very noisy PWM (not rectangular in shape but shape like that of capacitor charging) of 5V only, how do I increase this output voltage of PWM to say 8V??
Can you provide a scope capture of the GX_x outputs with and without a PWM?