SumGuy
Newbie level 2
We've been using Altera and Xilinx FPGA's in our PC-based data acquisition products for quite a while, and we use Altium software.
We have a project where we need to make a small battery-powered unit that must either (a) save data according to a simple pattern (15 minutes of continuous data every hour, every hour, every day for about a month) or (b) transmit the data a short distance to a PC or laptop (instead of logging the data).
Interfacing our FPGA to Nand-flash chips seems like a real pain, and I'm not sure if it's any easier if we used small SD-cards.
There are some small blue-tooth modules that are essentially wireless serial links (use about 23 to 35 ma of current when transmitting).
The data itself is a single 14-bit number, acquired at about 100 to 250 hz. We figure that 256 mbytes of memory is plenty.
We'd have an RTC dedicated to maintaining a time-stamp that the FPGA could read and write to memory once during every 15 minutes of data acquisition (daq), and we'd use the RTC's alarm to "wake up" the FPGA and turn on power to some analog circuits during daq. We already have a working USB interface to the FPGA, so that's what we'd use to read the data back out of SDram or Nand-flash when the 30-day daq is finished.
So basically what's easier? Logging or RF link? If logging, what memory (SD module or nand-flash connected direct to FPGA?).
We have a project where we need to make a small battery-powered unit that must either (a) save data according to a simple pattern (15 minutes of continuous data every hour, every hour, every day for about a month) or (b) transmit the data a short distance to a PC or laptop (instead of logging the data).
Interfacing our FPGA to Nand-flash chips seems like a real pain, and I'm not sure if it's any easier if we used small SD-cards.
There are some small blue-tooth modules that are essentially wireless serial links (use about 23 to 35 ma of current when transmitting).
The data itself is a single 14-bit number, acquired at about 100 to 250 hz. We figure that 256 mbytes of memory is plenty.
We'd have an RTC dedicated to maintaining a time-stamp that the FPGA could read and write to memory once during every 15 minutes of data acquisition (daq), and we'd use the RTC's alarm to "wake up" the FPGA and turn on power to some analog circuits during daq. We already have a working USB interface to the FPGA, so that's what we'd use to read the data back out of SDram or Nand-flash when the 30-day daq is finished.
So basically what's easier? Logging or RF link? If logging, what memory (SD module or nand-flash connected direct to FPGA?).