252 Threads found on edaboard.com: Lookup
for (i=0; i<=A_WIDTH; i=i+1)
demeta_param demeta_with_param (
ASIC Design Methodologies and Tools (Digital) :: 06-13-2007 08:30 :: leongch :: Replies: 0 :: Views: 669
nco is in fact a accumulator and a lookup table
you can realize a accumulator like this
if rising_edge(clk) then
acc(23 downto 0) <= acc(23 downto 0) + input;
end if; end process;
then, you can address the lookup table like this
if rising_edge(clk) then
nco_out(7 downto 0) <= rom(conv_
PLD, SPLD, GAL, CPLD, FPGA Design :: 05-31-2005 15:41 :: ddt694 :: Replies: 18 :: Views: 11233
Look for pin (Q),
then related pin : CK
timing_type : setup_rising
timing_type : hold_rising
( can be falling for negedge triggered flops)
then use the two lookup tables to interpolate the point and get the output transition/delay based on input transiiton/output cap.
ASIC Design Methodologies and Tools (Digital) :: 04-16-2007 05:47 :: rjainv :: Replies: 1 :: Views: 1877
put some gain & then use use precision rectifier.
For non-linearity you'll need to prepare a lookup table ( easiest way)
Microcontrollers :: 04-07-2007 19:02 :: lats :: Replies: 2 :: Views: 1348
You could use a PWM PIC output to generate analog input of two LM3914 IC's cascaded.
PWM duty-cycle will be allmost proportional to accquired distance.
A lookup table stored in flash program memory could give it compensation.
Microcontrollers :: 09-10-2007 20:18 :: andre_teprom :: Replies: 3 :: Views: 1010
When we implement the lookup table, we can use RTL or ROM. How to evaluate the cost between RTL and ROM? Thanks. May the small lookup table can be implement by RTL. The larger use ROM. What's the limit?
ASIC Design Methodologies and Tools (Digital) :: 03-12-2007 08:02 :: sunrisesky :: Replies: 0 :: Views: 906
lookup the current amplifier, perhaps it is helpful.
Analog Circuit Design :: 02-03-2007 13:55 :: watersky :: Replies: 14 :: Views: 5116
I want to implement a lookup table (rom memory) which comprise 362 cells, each one is 16bits ( so contains 2*181*16=5792bits). I prefer to use CPLD because it do not need any PROM in PCB. Can you suggest me a CPLD from XILINX (for example xc9500) that can implement this lookup table and two (16 bits) dividers and two multipliers?
PLD, SPLD, GAL, CPLD, FPGA Design :: 01-27-2007 11:33 :: ahmadagha23 :: Replies: 2 :: Views: 1679
Here is a simple and fast CRC-16 that I use. It is very fast since it uses two lookup tables.
unsigned short CRC16 ( puchMsg, usDataLen ) /* The function returns the CRC as a unsigned short type */
unsigned char *puchMsg ; /* message to calculate CRC upon */
unsigned short usDataLen ; /* quantity of byt
Microcontrollers :: 01-20-2007 01:20 :: servopump :: Replies: 8 :: Views: 2988
the difficulty is the input figures varies over a larg range,so I plan to convert them into remainders of 2pi to confine them in , and then feed the remainders into lookup table. I wonder if I could make a remainder in one clock cycle somehow. and how many cycles does a '%' calculation need in Verilog_HDL?
PLD, SPLD, GAL, CPLD, FPGA Design :: 01-12-2007 06:58 :: jason_tian :: Replies: 0 :: Views: 884
Are they still using table-lookup method to measure timing and power? Thanks.
ASIC Design Methodologies and Tools (Digital) :: 03-27-2007 17:01 :: trenton0225 :: Replies: 7 :: Views: 1554
I lookup the table of the chebyshev filter. The chebyshev filter I want to find is a third order filter with 0.5dB passband ripple. The polynomial I found is S^3+1.253*S^2+1.535*S+0.716.
What does the coefficient mean? It?s normalized to cutoff frequency, isn?t it? What?s the transfer function if the cutoff frequency is 4kHz and the gain is 0dB?
Analog Circuit Design :: 11-29-2006 08:17 :: renwl :: Replies: 4 :: Views: 1196
In Xilinx FPGAs, a Block RAM is a dedicated two-port memory containing several kilobits of RAM. The FPGA contains several (or many) of these blocks.
Inside of each small logic block is a configurable lookup table. It is normally used for logic functions, but you can reconfigure it as a few bits of RAM. You can combine several (or many) of them i
ASIC Design Methodologies and Tools (Digital) :: 11-03-2006 11:11 :: echo47 :: Replies: 17 :: Views: 67602
chevymn1964, did you use recomended NTC thermistor? It needs to have negative thermal coefficient - resistance goes donw with temperature decrease . If used thermistor is PTC - you will have backward effect - more temperature and less output.
author recommend Philips 2322-640-63103 NTC Thermistor. Yet it is not problem to use PTC thermistor - you
Microcontrollers :: 10-05-2006 00:01 :: artem :: Replies: 25 :: Views: 2747
Hi, i think the best way to do this is to make a lookup table with stored digital values of a single cycle of a sine wave and raster on this value with ur required frequency, also offcourse u need DAC to get ur analog signal.
Microcontrollers :: 09-06-2006 13:17 :: Bassem_fahmy :: Replies: 4 :: Views: 2620
Maybe this will you repeatedly add a constant to an integer accumulator, and then use the most significant bits of the accumulator as an index into a sinewave lookup table.
Please, can you upload the ddssim.zip file of that page as well as its useful
Software Problems, Hints and Reviews :: 08-21-2006 11:23 :: okguy :: Replies: 9 :: Views: 7361
IanP is correct, a lookup table would be the easiest since most likely you are only concerned about finding the natural log over a fixed interval of inputs.
An alternative is to calculate some number of terms of the Taylor series for ln(x).
The Pade approximation is simply another series which can be generated to approximate ln(x). The idea
Microcontrollers :: 07-28-2006 03:45 :: jonw0224 :: Replies: 5 :: Views: 5261
You can use lookup table which contains number of ones in one byte. Since the word is 4 bytes (assuming normal cpu), just add results from all four bytes. Or you can use some of these algorithms:
PC Programming and Interfacing :: 07-22-2006 04:13 :: cfant :: Replies: 8 :: Views: 1010
I'm trying to make a lookup table for a LED sign I'm making (hardware done, test program done and working).
But then I 1280(256x5) byte big lookup table.
I have read somewhere that I need to alter the PCLATCH register.
Any help would be great!
Or if anyone know of a better method of doing this?
EDIT: BTW i'm
Microcontrollers :: 07-17-2006 18:29 :: zanor :: Replies: 2 :: Views: 1422
Ok I have concrete question to those who knows AVR-GCC.
My data is in flash memory:
const uint8_t sinewave PROGMEM= //256 values
I have a function which outputs data from this lookup table to PORTD.
void signalOUT1(const uint8_t *signal)
Microcontrollers :: 06-30-2006 13:16 :: Mindaugasu :: Replies: 0 :: Views: 983