Hi, I'm trying to capture data from a device that uses the 2 edges of a 4Mhz clock to latch data to a 8 bits bus (so data frequency is 8Mhz).
So i'm using the external clock, which works great, except that OLS client only allows me to select either rising OR falling edge, not both!
I've read that with the internal clock, the 200Mhz mode uses both edges of the internal 100Mhz clock. So i believe it should be possible with the external clock too.
Is it a limitation of OLS client? And how could i achieve this?
Just after i posted my previous message, i've read this topic: http://dangerousprototypes.com/forum/index.php?topic=585.0. So it seems that even if settings are available in the application, there are very strict limitations to the really working settings. Using only 1 group (8 bits) seems to be forbidden, and also it seems that recording size is limited to 4K for 32 channels or 8K for 16 channels. So, since i'm using only 1 group, i'm out of these limitations! I have to make some more tests with allowed settings.
Thanks for your replies! This is the week-end, so i have time to come back to my problems!
@Sjaak: Ok for the missing rxtx library, i did not think about that because older version started correctly (i probably can't capture after). I will test later, i can keep using on my Mac for the moment. I use the probes provided by Seeeds, and i've also tested shorter cables (around 10cm long)
@Jack.gasset: Thanks for your advice. By grounding floating pins, results are no more random! I have either constant low or high levels, depending on the connection to VCC or GND. But i have another problem now, see below...
@sdixon: by random i meant constant level all along the capture, but all levels changing randomly between 2 captures.
So now that i know i must connect unused pins to ground, i've tried to capture a "real" signal (not only VCC or GND). Now, my new problem is that i only capture one constant signal, i can't capture level changes. i've first tried to capture serial data link (115200 bps, 3,3V): i can see the data on my terminal application, so serial link is working, but data captured by OLS is only a constant high level. I've then switched to another device using slower 9600 bps at 5V, with in addition a pulse signal on another pin: same results, only constant levels (high for the serial link, low for the pulse output, which is low by default). No serial data, nor any pulse are captured!
So it looks like i capture only an instant level, not sampling its evolution accross time.
Settings are the following: - Analyzer port: /dev/tty.usbmodem411 (there's also a /dev/cu.usbmodem411, i've not tried it) - Port speed: 115200 bps(LL) - Number schemes: inside - Sampling clock: internal - Sampling rate: tried different values between 1MHz and 200MHz - Channel groups: only 0 checked - Recording size: tried different values between 2K and 256K - Noise Filter: tried both - RLE: Off - Trigger: Off
Pretty basic configuration isn't it? And sampling rate of several Mhz should be far enough to capture 9600 or 115200bps.
May be am i missing something obvious, but i'm completely confused again...
I've received my brand new OLS a few days ago, but i can't manage to have it working correctly! When trying to capture, i get only random levels!
I've spent hours trying different versions of firmware or FPGA bitstreams, switching between Mac OS X 10.6.3 to Windows XP SP3, but i can't manage to have correct captures. I was almost sure to have a faulty buffer like in this thread: http://dangerousprototypes.com/forum/index.php?topic=540.msg4729#msg4729, but to be sure i've tried the self test function with firmware 0.4 and bitstream r2.04 (with Mac OS X since i can't have the r2.04 java client running in Windows: "Error while invoking application: null" message, but that's another problem!).
Surprisingly, the self test is absolutely OK! But even with this configuration, as soon as i try a "real" capture, it fails with random levels.
The test is very simple: i connect both GND probes to a GND pin, and i connect only one probe to VCC pin, either on an external device or on the OLS itself (using UART or ROM ISP pins). So when capturing, i should have only one channel high and all other channels low, but it never works! I got only random results.
I've tested the self test mode 3 times, always OK, but i can't manage to capture anything in normal mode :-(
