FAQ

Frequently Asked Questions

Below are commonly asked questions about QTrace:

QTrace doesn’t include a JTAG interface which is a big effort to implement and support. Every developer has at least one JTAG adapter so rather than covering the same ground as existing JTAG debuggers, we’ve been able to concentrate on developing robust trace functionality at a much lower price. Also, our mission is to allow developers with minimal tool budgets to experience the power of real-time trace. Until now, most have been put off by the hefty price tag.

It’s true; you can develop firmware perfectly well without trace. However, if you want to gain extraordinary insight into what your code is doing and you want to spot bugs quicker, with less effort and reduce your development time, then it’s definitely worth considering especially as trace is now affordable.

Yes, if it has a 20-way, 1.27mm pitch ETM trace header. If not, then a trace header will need to be added to your PCB.

Another option is to purchase our trace adapter for the very low cost Nucleo-144 demo boards from ST. This will allow you to trace code running on any of ST’s Cortex-M3/M4/M7/M33 devices that have ETM (most do).

No, not at all. ETM trace provides real-time instruction trace with no effect on processor timing.

No, QTrace only supports real-time instruction tracing as Cortex-M devices don’t typically offer data tracing. However, QTrace does allow you to stream and graph application data using the Cortex-M ITM interface, the output of which is merged with the trace data stream. The throughput of application data is lower than instruction trace and there is some CPU overhead.

ETM trace data is generated by the Cortex-M hardware to give real-time instruction-only tracing.

ITM trace data is predominantly generated by the application i.e. it affects timing and its throughput is much lower. It is used to transmit debug info such as program variables, ADC values, printf-style strings, RTOS trace info, etc. The Cortex DWT unit can be combined with the ITM to transmit hardware generated data such as interrupt latency and PC samples.

QTrace supports both protocols and its ITM data rate is much higher than a typical SWO implementation. QTrace Analyser also has a built-in ITM debug console and a waveform viewer.

QTrace has no ‘traditional’ trace buffer. Instead, it streams trace data via USB3.0 resulting in an unlimited trace capability. There’s no need to trigger, capture then upload & analyse a large trace buffer offline.

If your Cortex-M3/M4/M7/M33 device is ETM enabled and it adheres to the ARM timing specification then it should work with QTrace.

Contact us for clarification.

No. QTrace only supports Windows at this time.

A link will be sent to the email address given at the time of ordering a QTrace probe.

Please contact us if you don’t have the link.

No. Currently we only accept online orders with credit card payment.

Yes. We ship to all EU countries via DHL. However, you will need to pay any import taxes and duties imposed by your customs authority. When the item arrives in your country DHL will send a notification to the email address entered at the time of ordering stating the amount of import tax & duty to be paid before they will deliver to your address. Note that the process is generally efficient and will add minimal delay to shipping.

It is not possible to give an exact charge but it is typically VAT + 5% + a DHL administration charge of £16. For example, a QTrace probe costing £379 would likely incur an additional £95 in import tax & duty/VAT for a country with a VAT rate of 20%. Note that we will not charge VAT if you are outside of the UK. You can contact us before ordering for a non-binding estimate of the import tax & duty for your country.

Please Note: If you place an order and subsequently decline to pay import taxes due, DHL will charge us to return the item. We reserve the right to deduct this charge from the original sale price to be refunded.

No. At this time we only ship to the EU but we’re looking to expand this.

Feel free to contact us with any questions you have.