- Joined
- Apr 4, 2013
- Messages
- 884
Hi folks,
A few weeks ago a forum member (Backporch) reported some issues with touch probe functionality. Thread here for context: https://www.hobby-machinist.com/threads/touchdro-build-2024-03-11-beta.111246/post-1123631
After a bunch of digging and head scratching I found a bug in the first version of v2 firmware (it shipped on TouchDRO Glass/Magnetic scale adapters until late 2021. The issue is as follows:
The firmware correctly detects the default probe state, and when the probe is triggered, handles the event correctly, but the data stream uses the pin state to determine whether to send "p1" or "p0" signal (p1 = "probe is on" and p0 = "probe is off"). Since most non-conductive probes are normally-closed, when the probe is triggered, the input pin state goes from 0 ("low") to 1 ("high"), but since the Schmitt trigger inverts it, the code sees 1 => 0 and reports "p0" when the probe is triggered, and "p1" when it goes back to the default state.
The probe will still [appear to] work in TouchDRO, but it will not be as accurate as it can be (the expected latency for the off-to-on event is under 4us; on-to-off can be up to 100us).
Unfortunately v2 firmware doesn't have over-the-air update capabilities, so the only way to fix this is to send the board back to me for re-programming. Thus, I can offer two options if you have run into this issue:
1. Send the board to me and I will re-flash it with v2.1 firmware ("current" version for that adapter)
2. Once the [paid] upgrade to v3 firmware is available, I will offer discounts for adapters with 2.0 firmware.
If you are interested in option 1, please send me a message using the contact form on touchdr.com.
Thank you
Yuriy
A few weeks ago a forum member (Backporch) reported some issues with touch probe functionality. Thread here for context: https://www.hobby-machinist.com/threads/touchdro-build-2024-03-11-beta.111246/post-1123631
After a bunch of digging and head scratching I found a bug in the first version of v2 firmware (it shipped on TouchDRO Glass/Magnetic scale adapters until late 2021. The issue is as follows:
The firmware correctly detects the default probe state, and when the probe is triggered, handles the event correctly, but the data stream uses the pin state to determine whether to send "p1" or "p0" signal (p1 = "probe is on" and p0 = "probe is off"). Since most non-conductive probes are normally-closed, when the probe is triggered, the input pin state goes from 0 ("low") to 1 ("high"), but since the Schmitt trigger inverts it, the code sees 1 => 0 and reports "p0" when the probe is triggered, and "p1" when it goes back to the default state.
The probe will still [appear to] work in TouchDRO, but it will not be as accurate as it can be (the expected latency for the off-to-on event is under 4us; on-to-off can be up to 100us).
Unfortunately v2 firmware doesn't have over-the-air update capabilities, so the only way to fix this is to send the board back to me for re-programming. Thus, I can offer two options if you have run into this issue:
1. Send the board to me and I will re-flash it with v2.1 firmware ("current" version for that adapter)
2. Once the [paid] upgrade to v3 firmware is available, I will offer discounts for adapters with 2.0 firmware.
If you are interested in option 1, please send me a message using the contact form on touchdr.com.
Thank you
Yuriy
