8-bit or 32-bit microcontroller

I have a PLL IC (Hittite HMC702LP6E) which contains many registers for programming the IC among which the maximum length is 24 bits. I want to load data into these registers serially from a microcontroller.Do i require a 32 bit microcontroller or i can manage with 8-bit or 16-bit ones......

I could not locate the data on the HMC702LP6E before offering my thoughts on passing serial data, however, usually this can be done with one or more control lines, and may be done with any device which can meet the speed and interface requirements. Microcontrollers from 8 bits to 32 bits may often be used that can meet the speed and control line interface requirements. If the HMC702LP6E has "handshake" signals for serial interface, or can be programmed for any "handshake" signals you want to use with serial data, you should start with that. After you understand or decide what "handshaking" you must or want to use, then you may program just about any microcontroller to meet these requirments. The word length (16 bits, or 32 bits) is something you decide in the sending microcontroller, which you program. Good luck. David

Sorry my mistake...the IC no. is HMC702LP6CE....here is the link for the datasheet....the register maps are at the last of the document...
https://www.hittite.com/content/documents/data_sheet/hmc702lp6c.pdf

I have reviewed the data sheet for you, and the serial interface is very typical and may be done with any microcontroller. The timing requirements are not difficult at all. The logic is described for both seral read and serial write. While "SPI" might be used, you can easily interface to this serial interface with a simple "bit banger", that is - you generate all the timing and control from scratch, and it is no big deal. You'll want to select a microcontroller to support all the functions you need, but the serial interface is super basic. While your device is pretty fast, unless you need to issues commands really fast, even an 8 bit microcontroller can interface to your device. It is more about how many commands you want to issue and how you will interface your microcontroller to the real world. The 16 bit PIC family has more capability than one can write programs for in 6 months with room to spare. David

Thank you very much David for your response...actually I have no previous experience with microcontrollers....can i go for any popular 8-bit microcontroller for the application like atmega128 or pic18?....which one can be programmed using "C"....also I am unable to calculate how much flash,EEPROM and SRAM memory will be required for the application...I want to interface the MCU with a PC through DB-25 connector....the state-machine I want to implement with the MCU is roughly like this...The HMC702LP6CE IC is a PLL frequency synthesizer which locks to a certain frequency using one or more VCOs (voltage controlled oscillator) based on the frequency information data loaded into its registers....what i want to do, is before loading the registers directly I want to compare that frequency information with a preset value in the MCU to determine which VCO band to select and then load the data in the IC...also accordingly i need to send some control signals to few switches from the MCU to select the desired signal path...how much flash/eeprom/sram memory may be sufficient for this operations?....and all operations should be as fast as possible because according to my target specifications sending of freq. info to locking to a particular freq. must be completed within 100 microseconds...please suggest any appropiate MCU suitable for this....

When you have embedded tasks to do within a timeframe, you have to do your research, especially if you do not have time come up to speed on a new microcontroller, only to dicover it will not get the job done. Assembly code can be faster than C code, if you do it correctly, but you can write and debug more C code in a block of time. Some expert assembly code writers with years of experience may be an exception. C code is pretty good these days. In terms of speed, when a microcontroller can not get the job done, FPGA's, and other kinds of programmable logic is a direction to consider. To decide if any microcontroller may be fast enough, select one with a high clock speed and dig into the documentation. It will take from 1 to 3 days to qualify one, and you'll probably write some of your code "on paper" only in the process. MIPS is a benchmark to help qualify your task to the right programmable device. David

we are trying to interface a 8bit microcontroller to interface 3 sensors (heat,rpm,pressure) could anyone help us how it could be done.If u have the program,circuit anything pls mail it at (deepakkallandi@yahoo.com).

how are the sensors interfaced, e.g. ADC, I2C, SPI, etc? if ADC do you have three spare ADC inputs on the microcontroller?

akmo said:

we are trying to interface a 8bit microcontroller to interface 3 sensors (heat,rpm,pressure) could anyone help us how it could be done.If u have the program,circuit anything pls mail it at (deepakkallandi@yahoo.com).

Click to expand...

What are the sensors you are using? Posting the name or datasheet is likely to be very helpful in answering your question. Which microcontroller are you using?
You also need to understand the communication protocol, if it's linear voltage, serial communication (SPI, I2C/TWI), parallel communication, etc.

Hope this helps.
Tahmid.

akmo said:

we are trying to interface a 8bit microcontroller to interface 3 sensors (heat,rpm,pressure) could anyone help us how it could be done.If u have the program,circuit anything pls mail it at (deepakkallandi@yahoo.com).

Click to expand...

This may help...I have found it somewhere...it uses temperatur and humidity sensor with atmega MCU....it contains the program also...

we r using 89c51 microcontroller,sensor is LM35,PRESSURE sensor,adc 0804...send any details ...thank you very much for replying.....!!!!!!!!!!!