Hi friends

I am on the process of studying on feasibility for a new system for industrial applications.

The preliminary specs are

1. Display -> Graphical LCD display 240*128 single colour
2. Keyboard -> Proprietary KB/ PC
3. Data memory -> 256KB (serial /parallel/USB)
4. No of platforms -> 4 max
5. No of UART -> 2
One for -> RS232/RS485
Another for -> RS232/serial printing/ barcode scanner/ barcode printer
6. 4 to 20mA
7. USB device/host?
8. Ethernet
9. RTC
10. Digital inputs/outputs for controlling heavy loads -> 16
11. Parallel printer interface.

Application specs

1. General weighing scale (all 4 platform are updated )
2. Counting for each platform
3. Check weighing for each platform
4. Filling (oil/gas) for each platform.
5. Batch(mixing) weighing
6. Programming the parameters via RS232/RS485/USB/ETHERNET
7. Configurable parameters like
a. Communication parameters for RS232(MAY BE THROUGH KB ONLY)
b. Weight/count reference information
c. Setpoint values for each platform
d. Capacity/accuracy for each platform
e. Tare values for each platform
f. Reporting (Format to be fed)
g. Binding the values to the individual platform

The system basically meant for process industry and it is to be really very flexible, field configurable and each customer will be unique in our case.


I would like to have some guidance on basic approach like

1. Single powerful controller (>100MIPS) to many small controllers.
2. Feasibility on SBC based ARM
3. Operating system (uClinux)
4. File system (for storing data)
5. What is the USB protocol stack size
6. What is TCP/IP protocol stack size
7. Graphical user interface
8. Host software for USB
9. Development tools (hardware and software)
10. Development Time?

I made some study on ARM based controllers.

* Phillips LPC ARM series LPC21XX, they have upto 512kb code memory, USB, 2 UART, RTC, SPI, IIC, ADC, DAC, PWM, Timers, I/Os but Ethernet. I felt that with 512kb-code memory it is not possible to have TCP/IP and USB stack.

*. On LPC2220, it is with external memory access but no USB. I think can connect external USB and Ethernet chips.

*. Atmel A91SAM7X256 have USB, Ethernet, 2 UART etc with 256Kb-code memory, I feel code memory may not be sufficient

*. Ideally ARM based controller should have (I expect ??) Graphical display interface, USB, Ethernet, RTC, 2 UART, SPI, IIC, 10bit ADC (SAR) type, scratch pad memory 64KB and code memory 1024 KB? and 32 I/Os. I can interface non-volatile flash memory for weight with related info through USB/SPI/IIC.


Feel like asking for more than just help but I want to move on with right direction. Weighing related no problem but to USB and Ethernet things.

Please suggest some options/alternatives. I may get answers like it depends on what you are going to do with USB and Ethernet. You can assume how typically it is to be used.


Thank you for reading.




V.Nagarajan.