Hi I am designing a system which uses a small embedded processor(8052) to do general house keeping tasks,drive LCDs,read keyboard inputs etc and an Altera ACEX fpga to perform signal processing.The problem I have is that the customer wishes to be able to perform periodic updates to the fpga over tcp/ip which is do-able using a simple tcp/ip stack in the
8052 however where i am a little overwelmed by choices about is wether I should use jam byte code player in the 8052 with the original configuration data in code rom and reload new configuartion data into flash or put all the configuration data into flash and use a cpld to read the flash and configure the fpga in PS mode,or put the configuration data into flash and use the 8052 to configure the fpga in PPA mode. If anyone has any experiance of implementing this type of system or has any advice/comments all will be gratefuly received.
If you are stuck with the board (ACEX * 8052) then you have a kindof rough time ahead. You might use the LWIP stack (availablle on the internet) and some code available from Altera to do the JAM thing but it is going to be risky, slow and irritating.
Here is a plug for NIOS and the newer FPGAs. Consider this. Use a Cyclone (e.g. 1C6 -already bigger and faster than the largest ACEX) with NIOS (1 or
2). TCP/IP stacks already sorted out. Built-in CPU (very fast), enough FPGA area (for the rest of your FPGA requirements), cheaper config device (will probably save a lot comparing and EPC2 to an EPCS1 (when you prefer prom configuration)), NIOS comes with ASMI programming features that easily reprograms your config IC..... I can go on and on. You will be looking at one FPGA, one config PROM, one RAM chip (running at e.g. 16 bit width) and one Flashchip (but you might get away using a single EPCS1/4 IC to do all !!), the LAN chip and transformer you already require (+maybe a WDT). Much simpler PCB layout (everything now stars away from the FPGA), in-circuit programming, much easier in circuit debugging, more than one serial port and lots lots more (for about the same cost you are going to pay anyway)
I have just finished yet another NIOS based board that used to take 3 boards full of 8051s. 8051 CPUs are cute, but they can only go so far.
PLUS.... Impress you client but also have a bigger hold over him.
The reason why I write all this is because I did a similar design reconfiguring an older APEX20k FPGA from a configuration such as the one you are describing. Not worth it unless you have already spent all the money on the boards and/or you client has his heart set on the slowest system problematic system ever. Another thing, visualize how you are going to hold the entire config block in an 8051's memory, calculate a CRC + doing TCP/IP
Maybe You should use some hardware stack or at least Ethernet to serial device. Look at Tibbo homepage. And for configuring APEX FPGA I would use Atmel configuration memory. You can program that memory through I2C :)
Thanks for the comments guys,a couple of interesting idea to look into there,however I might be stuck with the 8052 as the customer is a very big fan of them and look s at you strangly if you mention to him that there are newer ones available ;)
Part of this decision will be based on headroom. If the 89C5x device has plenty of room, and the ACEX is small, then you can store config in on chip Flash. If you want to allow the most headroom, then you will save on chip flash for Code, and use a SPI memory for FPGA storage. If you choose a 89C5x with HW SPI, then you will be able to load the FPGA faster.
figure out what cost savings you can make, and take everything in account... struggling with 8051 code for maybe months, that's not even guaranteed to work; or a modern design which is finished in no time. Managers are always sensitive to money saving and meeting deadlines in time ;) If you can finish this in half the time for half the money, the 8052 sentiment will be gone.
A Jam player in 8052 will be slow and eat lots of code space, together with a TCP/IP stack I'm wondering if it would even fit in 64K of code space. Going to bankswitching is very complicated and expensive and ever slower. You're pushing the humble 8052 far too far, I'm afraid...
Cyclone's are cheap, config devices are cheap, NIOSII is easy to use. For $995 you have a complete design kit. Seems like a lot of money, but writing software that's not going to work is far more expensive.
The problem has been solved by the use of a compact flash memory card on the board which is going to be used to hold the configuration data and the results from the signal processing which can both be transfered by tcp/ip. So thanks for all the advice but the solutuion we are going with is a good one and its easy to implement some simple ide driver code for the
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.