[Moved] Reducing pin usage in microcontroller

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ajitnayak

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DEAR ALL.

I am using(LaunchPad MSP430G2553)

I am having totally 16 pins available I.e GPIO other than gnd/vcc/RST

i have totally 20 pin as out put.

4 for speed selector like 100,200,300,400,600in rpm using potentiometer
4 for motion control selector fw,rv,stop using potensiomete
2 for motor drive
2 for analog sensor
2 RTC pin
2 for GPS
4 for operation selector-> init ,manual, automatic,use defined.

Is there any way to reduce pins for connection. I never want to go with resistor selector network. If any other method, please me the link
 

Re: Reducing pin usage in microcontroller

Are u using any standard interfaces? like I2C
 

Re: Reducing pin usage in microcontroller

yes i have mentioned in thread ,RTC uses I2c Interface.
 

Re: Reducing pin usage in microcontroller

In that case u can share the bus right..if u have similar interfaces..
 

Re: Reducing pin usage in microcontroller

i am having single RTC . other are digital pins .i wanna know is there way to minimise my pin external circuits
 

Re: Reducing pin usage in microcontroller

4 for operation selector-> init ,manual, automatic,use defined.
Use analog for this with only 1 analog you can take all 4 swicth

USe R , 2R , 4 R, 8R, 16 R in serie, and put each button in paralell with the resistor, You can know easily what buttom is pressed just checking the bits on AD
 

Re: Reducing pin usage in microcontroller

I never wannt to go with Resistor circuit.SInce module will be placed in high temp zone. it might degrade.on temperature . So i wanna go without resistor combination


 

The use i2c comunication, This means your pins will be serialed coded and decoded by software
 

if you have any links please share it.How they accessing digital output through software


ebclr said:
The use i2c comunication, This means your pins will be serialed coded and decoded by software
Click to expand...
 

Hello!

Just for my understanding:

4 for speed selector like 100,200,300,400,600in rpm using potentiometer
Click to expand...

I don't get it: you want to use digital inputs or a potentiometer?
In case of digital inputs, if you remove just one selection, then you can deal with 2 bits:
00 -> 100rpm
01 -> 200
10 -> 300
11 -> 600
If your really need 5 values, then you need 3 bits, and there will be 3 unused positions.
-> 3 bits

4 for motion control selector fw,rv,stop using potentiometer
Click to expand...

Again, I don't get it. Forward / reverse is 1 bit. And go / stop is another bit.
-> 2 bits

2 for motor drive
Click to expand...

If it's a plain DC motor, you can drive it with a single bit. (including forward / reverse.
-> 1 bit

2 for analog sensor
2 RTC pin
Click to expand...

Is it a I2C device?
-> Ok for 4 bits

2 for GPS
Click to expand...

UART?
-> Ok for 2 bits

4 for operation selector-> init ,manual, automatic,use defined.
Click to expand...

I guess you cannot have simultaneously manual and automatic. This will be 1 bit/
Init, yes, maybe. Use defined, do you mean user defined? Anyway, this is 3 bits
-> 3 bits

-> Total: 15 bits. Should be OK for 16 GPIO.

Dora.
 

This is right combination i m currently using
00 -> 100rpm
01 -> 200
10 -> 300
11 -> 600

bit specified below refer to the out put pin or input pins i m connecting to. I m having only one I2c i.e ds1307 which occupies 2 pins SDA and SCL on board. analog sensor 2 refers, 2 analog output since they occupies 2 pins.So i need method of reducing pins without affecting their functions






 

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