HET setup for sin table plus external /internal triggering

Hello Ian,

  I think you can extend the Sine Wave NHET program to generate an event at sample 125 to the ADC so the the ADC will start conversion. You can also generate an interrupt when the sample 127 is reached so CPU can set a GIO pin in the ISR. When the ADC conversion completes, it also generates an interrupt to the CPU. In the ADC completion ISR, you will clear the GIO.

 Since NHET is a coprocessor, there are multiple ways to write the software. Below is just one example. Below example assumes 12 samples per sine wave. So each sample is equal to 30 degrees on the sine wave. This example will assert NHET1[8] pin at the 8th sample. NHET1[8] is internally connected to ADC1 as one of the conversion event inputs. Please check the datasheet of your device for available trigger inputs to the ADC. You can extend the program to cover other scenarios.

PWM_PERIOD            .equ 11
PWM_PIN_NUM           .equ 9
INIT_COMPARE          .equ 6
INIT_HR_DELAY         .equ 0
ADC_TRIGGER_PIN       .equ 18
SAMPLE_TO_TRIGGER     .equ 7

L00   CNT { reqnum=0,request=GENREQ,reg=A,irq=OFF,max=PWM_PERIOD};
L01   ECMP { next=L03,hr_lr=HIGH,en_pin_action=ON,cond_addr=L02,pin=PWM_PIN_NUM,
             action=PULSELO,reg=A,irq=OFF,data=INIT_COMPARE,hr_data=INIT_HR_DELAY};
L02   MOV32 { remote=L01,type=IMTOREG&REM,reg=NONE,data=INIT_COMPARE,hr_data=INIT_HR_DELAY};

; Only execute the below instructions when Z flag is detected. Z flag is set
; when one PWM is complete. One PWM period means one sample point in the sine wave.
L03   BR { next=L06,cond_addr=L04,event=Z};
L04   CNT { next=L05,reg=B,max=PWM_PERIOD,data=0};
L05   ECMP { next=L06,en_pin_action=ON,cond_addr=L06,pin=ADC_TRIGGER_PIN,action=PULSEHI,reg=B,data=SAMPLE_TO_TRIGGER, hr_data=0};
L06   BR { next= L00, cond_addr=L00, event= NOCOND }