Choosing Microcontroller and ADC

[shahinjc]

hi guys

i have voltage between 500 microvolt to 5 volt then it passes from a amplifier , i need a 12 bit ADC , my frequency is low about 50 hz do u guys have any suggestion what ADC i choose ? i need a cheap ADC

and after ADC i need to process that information with a microcontroller , do u guys have any suggestion about microcontroller which is compatible with that 12 bit ADC?
any suggestion?:grin:

 

[paulfjujo]

hello,

as suggestion :
PIC18F4553 with ADC 12 bits !
or if you don't have other I/O to treat a simple PIC12F1840 + ADC MCP3304 = 8 ADC 12 bits driven with SPI link
PIC18F46K22 ( very confortable PIC with a big amount of RAM and ROM) + ADC MCP3304
an tested example with C18 code on my web page
with PIC18F252
+ 5 ADC 10 bits
+ 8 ADC 12bits SPI link MCP3304
+ 4 ADC 17 bits I2C link MCP3424 (
+16 inp + 16 outp with 2 x MCP23017 I2C link
+ RS232

 

[shahinjc]

hello,

as suggestion :
PIC18F4553 with ADC 12 bits !
or if you don't have other I/O to treat a simple PIC12F1840 + ADC MCP3304 = 8 ADC 12 bits driven with SPI link
PIC18F46K22 ( very confortable PIC with a big amount of RAM and ROM) + ADC MCP3304
an tested example with C18 code on my web page
with PIC18F252
+ 5 ADC 10 bits
+ 8 ADC 12bits SPI link MCP3304
+ 4 ADC 17 bits I2C link MCP3424 (
+16 inp + 16 outp with 2 x MCP23017 I2C link
+ RS232

thanks for your suggestion , actually i just worked with AT mega series microcontroller
are the for example PIC18F4553 is the same with AT mega ? can i program it ,
and my process which i'm gonna do on this information is not complicated so i just need cheap microcontroller
you seems master in this stuff , do u have any other suggestion?

 

[jayanth.devarayanadurga]

Use any adc from LTC. They are very good. You get 10, 12, 16, 24 bit ADCs from LTC (linear technologies). They have I2C and SPI ADCs.

 

[shahinjc]

Use any adc from LTC. They are very good. You get 10, 12, 16, 24 bit ADCs from LTC (linear technologies). They have I2C and SPI ADCs.

when i search i see these ADC's are high frequency but my frequency is 50 HZ
do u any microcontroller compatible with these ADC's?

 

[jayanth.devarayanadurga]

I have used LTC with PIC and AVR microcontrollers. They work fine.

- - - Updated - - -

See this simulation.

I can write the code so that it works with the uC you want. Mention the uC you want to use.

Edit 2:

tpetar is right. If you use 16-bit ADC resolution will be (5 V/65535) = 0.00007629510948348211 V = 76.29510948348211 uV.

 

[paulfjujo]

hello

are the for example PIC18F4553 is the same with AT mega ?

sorry, it's not the same familly of microcontrolers.. not compatible with ATMEL, even using C langage.
but you can work with every kind of ADC wich support I2C or SPI protocol..
with ATMEL microcontroler.

I don't know if ATMEL has microcontroler with inbuilt 12bits ADC, like on microchip.

Your frequency is 50Hz, a low frequency
but what sample rate do you need... How many measures per period of signal ?

LTCxxxx are also good ADC, i tested a LTC1286 12 bits .. up to 100.000 samples per second on other application.
but, don't forget to keep some processor time to do other task in your main program,
like display the value or ....

 

[tpetar]

hi guys

i have voltage between 500 microvolt to 5 volt then it passes from a amplifier , i need a 12 bit ADC , my frequency is low about 50 hz do u guys have any suggestion what ADC i choose ? i need a cheap ADC

and after ADC i need to process that information with a microcontroller , do u guys have any suggestion about microcontroller which is compatible with that 12 bit ADC?
any suggestion?:grin:

500µV is 0,5mV

10-bit ADC have 4,88mV step.

12-bit ADC have 1,22mV step.

14-bit ADC have 0,305mV step.


This means you cant use 10-bit or 12-bit ADC for this purposes, you need at least 14-bit ADC if you want to measure that low values.



Best regards,
Peter

;-)

 

[shahinjc]

I have used LTC with PIC and AVR microcontrollers. They work fine.

- - - Updated - - -

See this simulation.

I can write the code so that it works with the uC you want. Mention the uC you want to use.

Edit 2:

tpetar is right. If you use 16-bit ADC resolution will be (5 V/65535) = 0.00007629510948348211 V = 76.29510948348211 uV.

thank you , you are the best , soon i will contact you , thanks for your helps

- - - Updated - - -

500µV is 0,5mV

10-bit ADC have 4,88mV step.

12-bit ADC have 1,22mV step.

14-bit ADC have 0,305mV step.


This means you cant use 10-bit or 12-bit ADC for this purposes, you need at least 14-bit ADC if you want to measure that low values.



Best regards,
Peter

;-)

thanks you are right , this was really helpful , i'm gonna use 14 bit ADC

 

[tpetar]

Check Maxim-Integrated Precision ADCs :

https://www.maximintegrated.com/products/data_converters/adcs/precision-adc.cfm



Best regards,
Peter

 

[jayanth.devarayanadurga]

How about these?

http://cds.linear.com/docs/en/datasheet/215314f.pdf

http://cds.linear.com/docs/en/datasheet/231414f.pdf


14-bit 310 Msps ADC Parallel Interface
14-bit 4.5 Msps ADC SPI Interface

 

[pasicr]

Hi for all,
https://www.ti.com/ww/en/launchpad/msp430_head.html
that is the chipest dev board in the world, app 10 USD
great performance, easy to programming, ADC included,
best regards

 

[tpetar]

Hi for all,
https://www.ti.com/ww/en/launchpad/msp430_head.html
that is the chipest dev board in the world, app 10 USD
great performance, easy to programming, ADC included,
best regards

MSP430 is small dev board not ADC.

 

[pasicr]

Zdravo Petre,
Hi Peter, you are right,
this dev board come with/support MSP430G2xx2, MSP430G2xx3, and MSP430F20xx devices in PDIP14 or PDIP20 packages,
all have integrated peripherals such as 8ch 10-bit ADC, timers, serial communication (UART, I2C & SPI) & more!
regards

 

[tpetar]

Hi Pasicr,

I saw it now that you are from Macedonia, greetings.


He need at least 14-bit ADC, because 10-bit and 12-bit have to small resolution for his needs.



Best regards,
Peter

:wink: