Search found 8 matches

by jcsbanks
Sat Apr 15, 2017 7:30 pm
Forum: ESP32 HDK
Topic: About the CAN controller.
Replies: 112
Views: 28368

Re: About the CAN controller.

First eight packets are with a FreeRTOS task replying with an echo of packets received, so four are sent, four received. Second eight packets are with the reply in an ISR. Moving from FreeRTOS to an ISR drops the latency 20 times from average of 5.3ms to 260us.

latency.png
latency.png (18.63 KiB) Viewed 1805 times
by jcsbanks
Wed Apr 05, 2017 12:36 pm
Forum: ESP32 HDK
Topic: About the CAN controller.
Replies: 112
Views: 28368

Re: About the CAN controller.

It is working with MCP2551. Kvaser log, I sent 8 zeros in the first three packets, then 0, 52 then six zeroes in the subsequent packets and the ESP32 echoes them. The 2018 is the CAN ID, 8 is the DLC, then the payload, then the timestamp and Transmit or Receive. 0 2018 8 0 0 0 0 0 0 0 0 66.129150 T ...
by jcsbanks
Thu Mar 30, 2017 11:14 am
Forum: ESP32 HDK
Topic: About the CAN controller.
Replies: 112
Views: 28368

Re: About the CAN controller.

Connecting the D pin of the tranceiver to 3.3V, I read -1.1mV between CAN H and CAN L with the bus disconnected but with 120R termination. Connecting the D pin of the tranceiver to 0V I read 0mV between CAN H and CAN L. I should be getting a positive voltage between CAN H and CAN L in this situation...
by jcsbanks
Thu Mar 30, 2017 10:43 am
Forum: ESP32 HDK
Topic: About the CAN controller.
Replies: 112
Views: 28368

Re: About the CAN controller.

Thanks rudi. Yes I am using Kvaser Leaf Light v2 HS with OBD plug. SN65HVD230 CAN bus tranceiver (3.3V). Kvaser Leaf CAN H to SN65HVD230 CAN H. Kvaser Leaf CAN L to to SN65HVD230 CAN L. Kvaser Leaf GND pin 5 (signal ground) to to SN65HVD230 GND. I will try Kvaser Leaf GND pin 4 (chassis ground) and ...
by jcsbanks
Wed Mar 29, 2017 4:00 pm
Forum: ESP32 HDK
Topic: About the CAN controller.
Replies: 112
Views: 28368

Re: About the CAN controller.

Bit more info after playing all afternoon. The Tx pin is connected to the tranceiver from pin on ESP32 Devkit C to pin on the tranceiver chip, but the ESP32 cannot transmit. Pulling either Tx or Rx connection from ESP32 to tranceiver stops reception. The ECU only sends a single packet (but repeatedl...
by jcsbanks
Wed Mar 29, 2017 11:38 am
Forum: ESP32 HDK
Topic: About the CAN controller.
Replies: 112
Views: 28368

Re: About the CAN controller.

Wow rudi, that is awesome, thanks very much! This is an amazing chip and forum, great support, you deserve to sell billions of ESP32. I have got the ESP32 and a CAN bus tranceiver hooked up to a Kvaser Leaf Light, with termination resistance. I can send a frame from Kvaser and the ESP32 receives it,...
by jcsbanks
Tue Mar 28, 2017 8:42 pm
Forum: ESP32 HDK
Topic: About the CAN controller.
Replies: 112
Views: 28368

Re: About the CAN controller.

As a follow up, the demo compiles fine if I compile it as it is in the zip, so I've removed version 0.1_third_parts. I can also see that I could: CAN_frame_t __TX_frame; ...and then set the ID with: __TX_frame.MsgId Which is quite useful as I want to transmit and receive on multiple CAN IDs.
by jcsbanks
Tue Mar 28, 2017 8:22 pm
Forum: ESP32 HDK
Topic: About the CAN controller.
Replies: 112
Views: 28368

Re: About the CAN controller.

Great work on this! Great device! Received my ESP32 today and trying to compile CAN example. I thought it was best to clone version 0.1_third_parts and the menuconfig includes the options and saves them correctly. I copied main.c from http://www.barth-dev.de/wp-content/uploads/2017/01/ESP32_CAN_demo...

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