query on choosing controller for floating operations

[ravichandru]

Hi all,

i wanna do a project on voltage to frequency converter in that the voltage which i am giving is -60mv to +60mv i wanna get fraction part too in htis like 1.02mv like this for this to achive i need floating point operatable controllers can any suggest me which is good for this. here i wanted to send the readings to serial terminal but in serial communication the register can hold only char or int but not float i wnat such is thr any such.

 

[poorchava]

The whole question comes down to how fast has it got to be. As you probably know, float operations take large amounts of code and data memory as well as many cycles to perform. I think you might need something with large program memory and a bit of ram. If you don't need high throughoutput this can be almost any mcu with sufficient memory. I've seen a PID temperature regulator operating on floats made with ATMega16, it could do some tens of iterations per second clocked at 16 MHz.

So if you are not after speed, when I'd say go with AVR. PIC18 could also do but has inferior processing power compared to AVR and the C18 compiler doesn't handle floats very well.

If you are after speed, then you could use something from PIC24H or dsPIC33 families. They operate at up to 40 MIPS which is a lot of processing power. The better choice would be dsPIC33 at it has some DSP functionalities which might come handy. I think ARM Cortex M-3 processors are also an option, as they have high processing power and usually lots of memory.

If you needed REALLY HIGH throughoutput you might need something with hardware floating point operation unit, but those might proove to be very expensive and hard in application. I can't think of anything specific right now (but that's probably because it's 6.50 in the morning right now... :/) but i guess TI and Renesas might have something like that.

 

[nikhilele]

TI DSP MSP Series
or DSP PIC dsPIC

with proper library you can do it in simple 8051 also

 

[ravichandru]

Thanks for your suggest i have choosen ARM Cortex bcz i need ethernet compatability too for my work so its the best option.

 

[poorchava]

If you need ethernet compatibility you might want to consider Freescale MC9S12NE64 MCU. It's a 16-bit 25 MIPS MCU with integrated EMAC and PHY which means that only thing you need to connect in order to gain ethernet capability is magnetics and RJ connector (there are integrated connectors with magnetics available for around $4).

Check out the datasheet here: NE64 at Farnell website