Thinking of migrating from MC705C8ACPE to an 8051

[Scott]

My company has a product that is currently controlled using a MC705C8ACPE. That controller has become obsolete and there is no direct replacement.  We would like to migrate to something that is similar and perhaps switch to a SMD.  Do you have any recommendations for a very similar replacement or another processor we could use that will probably be around for the next 15 years.  We are thinking about moving to an 8051 family processor.  I know that is pretty old technology and is not very similar to the MC705C but there are about 20 companies that manufacture drop-in compatabile chips so it should be around for quite awhile. 

 

The function of the program is fairly simple.  It's basicly an adjustable timer that counts down a cycle time and monitors water level in an open pan of boiling water. The controller monitors the water level using three magnetic reed float switches and opens a solenoid valve to add water when needed. It also turns on and off the the heaters that heat the water. When a cycle is running, the heaters are on for the duration of the cycle. When the cycle is over the heaters turn off.  Between cycles the water temperature is maintained at 180 deg f.

 

Do you have any recommendations for a controller that may be very similar to the MC705C8A or which controller we might want to migrate to?  We do not currently have any hardware/software development tools so will need to purchase what is required.

 

The inputs and outputs are as follows:

 

Inputs (6):

Start button

Timer Button

Water Temperature (comparator circuit with thermister)

High water float switch (Vcc, two states, open/closed)

Add water float switch (Vcc, two states, open/closed)

Low water float switch (Vcc, two states, open/closed)

(Vcc is 5V)

 

Outputs (5+):

Heater control (on or off, nothing in-between. Currently an onboard opto-coupler circuit controlling three 24VAC contactors. May migrate to SSR)

Water control (on or off. Onboard opto-coupler circuit controlling a 24VAC solenoid valve.)

4 seven segment LED displays  (We want to migrate to an LCD display)

Piezoelectric buzzer

 

LED Outputs: (All LED lights will probably be integrated into the LCD display)

Preheat LED light 

Ready LED light 

Steaming LED Light

Adding Water LED light

Cool Down LED light

[Ashutosh Bhatt]

your project seems to be very interesting and simple also. you hv described it very well

you can use any controller for this. 89C52/89S52, or ATMega16/32 or PIC  controller

i suggest AVR ATMega16 will be the better option.

[Scott]

Thanks for your assistance. Why do you think the AVR ATMega16 is a better option?

[Author]

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