Fix hang while waiting for CAN heartbeat on multi-ODrive systems

When using the Teensy's built-in CAN peripheral, pumpEvents will
effectively only process the 16 messages in the Teensy's CAN mailbox.
This is in contrast to the MCP2515, which uses an interrupt, and the
Arduino R4 CAN peripheral, which is dequeued to up to 100 messages.

Previously, we delayed for 100ms after (unsuccessfully) processing
incoming messages for a heartbeat message. As a result, when using
systems with more than one ODrive, and/or an extremely high number
of messages per second, the Teensy's mailbox will fill before the
heartbeat is recieved, and thus discard future messages.

This issue is exacerbated by the default 100ms period of the ODrive's
heartbeat message -- in short, the ODrive would always send a heartbeat
message at the same time relative to the Teensy reading the mailbox, so
unless the timing was such that the heartbeat was in the first 16
messages during the delay, it would be missed. For most users, minute
differences in the ODrive and Teensy's clock accuracy would cause a
timing skew that would eventually bring correct this, however this could
take up to 30 minutes, if not indefinitely long.

Author: solomondg

CHANGELOG.md

@@ -1,3 +1,6 @@
+# [0.10.8]
+- Removed delay while waiting for heartbeat message, causing infinite/nondeterministic delays on some Teensy-based systems with multiple ODrives.
+
 # [0.10.7]
 - Fixed int overflow issue w/ Arduino Mega example
 

examples/SineWaveCAN/SineWaveCAN.ino

@@ -224,7 +224,6 @@ void setup() {
   Serial.println("Waiting for ODrive...");
   while (!odrv0_user_data.received_heartbeat) {
     pumpEvents(can_intf);
-    delay(100);
   }
 
   Serial.println("found ODrive");

library.properties

@@ -1,6 +1,6 @@
 # https://arduino.github.io/arduino-cli/0.33/library-specification/
 name=ODriveArduino
-version=0.10.7
+version=0.10.8
 author=ODrive Robotics Inc. <[email protected]>
 maintainer=ODrive Robotics Inc. <[email protected]>
 sentence=Library to control ODrive motor controllers