Difference between revisions of "InsideGadgets Logic Observer"
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Latest revision as of 19:08, 23 August 2015
| Status | planned |
|---|---|
| Channels | 8 |
| Samplerate | 50MHz |
| Samplerate (state) | — |
| Triggers | high, low |
| Min/max voltage | 2V — 5.5V |
| Threshold voltage | ? |
| Memory | 131ksamples/ch |
| Compression | none |
| Website | insidegadgets.com |
The insideGadgets Logic Observer is an 8-channel logic analyzer with up to 50MHz sampling rate. It is a mostly open project with all source code (CPLD, MCU) available, as well as a schematic of the PCB.
See insideGadgets Logic Observer/Info for more details (such as lsusb -v output) about the device.
Hardware
Protocol
The device is controlled entirely via USB control messages. The command is encoded in the request value of the control message; value and index are unused.
The following requests are defined:
USB_TRANSFER (1)
This tells the device to transfer the samples captured in memory to the host. This is called multiple times; the buffer memory is transferred 254 bytes at a time, with the address increasing automatically. The address is reset when a capture is started or settings are updated.
USB_SETTINGS (2)
Send new settings to the device. The settings consist of the following eight bytes sent along with the control request:
| Byte | Description | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | Bitmask of the channels to trigger on. All channels marked according to the trigger level must match before a trigger is considered to have fired. | ||||||||||||||||||
| 1 | Level to trigger on (0 or 1). | ||||||||||||||||||
| 2 | Delay after trigger, in milliseconds. | ||||||||||||||||||
| 3 | Trigger count: number of times the trigger must fire before the capture starts. | ||||||||||||||||||
| 4 | Sample rate, as follows:
| ||||||||||||||||||
| 5 | Number of samples to capture | ||||||||||||||||||
| 6 | Start capture flag: a capture is started if this is not 0. | ||||||||||||||||||
| 7 | Always 0. |
USB_STATUS (3)
Returns a 2-byte status field. The first byte indicates whether capturing has finished (1) or not (0). The second byte is always 0.
USB_CANCEL (4)
This cancels a capture in progress.