Are you familiar with the 80-20 rules? In our case, it means that 80% of us use only 20% of the functions we have. Put in context, 4 channels will cover all your needs if you’re working with serial protocol.
I2C, SPI, 1-Wire, UART, RS232, CAN BUS, LIN, Manchester, (and many more). All those are covered by the 4 channels of ScanaQuad.
It's a simple yet tough question. We provide 4 models of SQ logic analyzers in a way that every user can find a device that matches his needs and budget.
* SQ25 will do just fine if you need to debug very simple stuff, like LEDs toggeling on an arduino or simple USART packets capture.
* SQ50 and SQ100 will give you more memory depth (so that you can capture signals for longer periods). It's perfect for most usages, like debuging a USART communication or checking why an I2C sensor aint responding.
* SQ200 will cover even more application. With it's 5ns resolution, you can easily capture high speed SPI or JTAG transactions for example.
If you're in doubt and don't know which device is best for your application - drop us a mail or call us, and we'll be happy to give you more hints.
Mixed mode, is the ability to capture and generate simultaneously. Being able to capture and generate logic patterns simultaneously with the same tool, is a unique and exclusive feature of ScanaQuad. It comes in extremely handy when debugging Logic signals. For instance, you can build an I2C packet, inject it into an I2C bus, and capture the response of a chip, all with ScanaQuad in just a few minutes.
ScanaQuad does not stream signals via USB. Instead, signals are captured and stored into internal memory buffers before being transfered to computer. There is a main reason for that: ScanaQuad can capture and generate signals simulateneously, at sampling rates up to 200 MHz. That's too much to ask for USB, specially if data is being transfered both from and to the logic analyzer / signal generator.
Not right away. ScanaQuad hardware was designed with this exact feature in mind. A low-cost accessory will be released in 2017 to allow combining up to 3 ScanaQuad together, totaling 12 channels perfectly synchronized, as if it was a single logic analyzer. This accessory will even provide BNC connections for trigger IN/OUT.
Absolutely, yes! SQ200 devices can captures 200 million samples per second on all 4 channels (or generate 200 million samples per second).
That’s a tough question, and there is no direct answer to that. Only rule of thumbs. It all boils down to “how many samples you need per period of your signal”.
Some vendors will tell you that you need to have at least 4 samples per period (i.e. that the sampling rate be 4 times higher than your fastest measured signal).
We consider you should have at least 8 sampling points per period.
So, to recap, here are the maximum frequency that can be reliably captured with ScanaQuad devices:
- SQ25: 6 MHz
- SQ50: 12 MHz
- SQ100: 25 MHz
- SQ200: 50 MHz
ScanaQuad devices can generate signals, you probably already know that. However, in some situations, one needs to switch between input and output within a single data transaction. The most famous example for that is I2C communication, but it’s true for many other buses where both master and slave devices drive the same data line.
ScanaQuad has Open-Drain outputs specifically to allow easy interfacing to such buses.
For instance, with a ScanaQuad device that has Open-Drain capability, you can quickly generate some I2C requests, and record the response of the device under test. Without any fancy interfacing circuitry or strange diode based connections!
Like any Logic Analyzer, ScanaQuad works with a set of probes that connects the analyzer to the circuit. The probes are about 20 cm in length. That’s not negligible in modern electronics and can be a source of noise. That’s why, we put 100KΩ pull down resistors to “pull down” any floating or weakly driven lines.
In some rare situations, 100KΩ input resistance is too small, and may alter your circuit’s operation. That’s when the 1MΩ input impedance come in. When ScanaQuad is configured with 1MΩ input impedance, it will have an unnoticed impact on your circuit operation, making the measurements even more precise.
Absolutely, yes! That is possible on SQ50, SQ100 and SQ200 devices.
however, SQ25 devices only support CMOS and TTL levels in between 0V and 5V.