Tlc549proteus simulation &sallen key filter &ad736vrms to DC conversion &proteus view 51 register value

As the title , This blog is about 4 Block content , But it was solved through a small experiment ！
It turned out that there was a homework problem that said it should be used 51 and TLC549 Measure the effective value of low-pass voltage , Think about using the effective value to DC transformation , So use the AD736 Chip emulation .

Sallen-Key Low pass filtering principle

Send a letter ： It is a second-order low-pass filter

Parameter selection and circuit connection

A little bit , I don't know whether it's because of simulation or really , Input 1Hz The signal of AD736 It can't be imitated , added 10Hz Just fine , then RC The choice is 1k and 10uF, According to the above formula, it is w0=100（rad/s）.

Then enter sine , amplitude 1V, Filter output amplitude 0.7V about , Valid values 0.5V about .

AD736 The connection method of is as above .
From the voltage probe, it really is 0.5V about .
The back is AD736 Output termination AIN,P1.5 Pick up DO,P1.6 Pick up SCK,P1.7 Pick up CS Not , The two capacitors are used for filtering .

The whole circuit is almost like this ：

Simulation process and results

use Proteus Looking at registers is simple , Because I'm running in a loop , There is no need to stop at any step , So first click Run at the bottom left , Then click debug （debug） Pause in the drop-down list , Then move the cursor to 8051CPU here ：

Choose registers from the things that pop up （Register）, Of course, if you want to see others, it's convenient to order others .
The result of the transformation is theoretically 1AH：


The result of conversion is that I exist R6, You can see that the simulation result is the same as the calculation of Yimao , The experiment is finished .

TLC549 sequential

The book says CS You have to wait for two rising edges after pulling down , I believe , The result I made at the beginning was 68H, just 1AH Of 4 times , Because there are two missing 0, Wait for these two rising edges .
Actually CS After pulling down SCK High level direct reading 8 I'll be fine ,CS You need to wait after non lifting 36 A cycle （ The book says, , Maybe not necessarily , But the result is no problem ）.

Program

Assembly write timing ratio C convenient ,C Is slightly better than assembly in integration , Of course, what I use here is compilation ：

	CS BIT P1.7
	SCK BIT P1.6
	DO BIT P1.5
	ORG 0000H
	START:SETB CS
	CLR SCK
	SETB DO
ADC:MOV A,#0
	MOV R0,#08H
	CLR CS
	CLR SCK
	LP1:CPL SCK
	NOP
	MOV C,DO
	RLC A
	CPL SCK
	NOP
	DJNZ R0,LP1
	SETB CS
	MOV R6,A
	MOV R0,#48H
	LP4:CPL SCK
	NOP
	DJNZ R0,LP4
	AJMP ADC
	END