mikeleslie
Active member
I have a project where I'm connecting a Teensy 3.5 via serial to a esp8266 and am having a strange problem. I can not get the TX and RX pins to work on the same teensy port (say serial2) when they are talking to each other.
Both devices work fine in a loopback test (connecting the TX to the RX.) and the teensy works fine in loopback with serial1 and serial2. When I have the issue is when I connect the 2 devices together. The both share the same power and ground.
If I connect the TX and RX pins on serial2 to the esp pins, the esp will not receive any data but can send. Same situation on serial1. If I connect the teensy TX on serial2 and RX on serial1 it works fine. basically I can not send and receive on the same teensy port if it attached to the esp device.
some details:
all serial at 19.2k
data packets about 50 chars, once every second
teensy 3.5, ide1.87 teensyduino 1.48
heltec htit w2866 for the esp board
the wire length for the serial connections is 6 inches.
I have SPI included as well as modbusmaster (tied to serial3)
I've been using serial comms on teensy's for years and never really seen anything like this, although admittedly I usually put a max232 between them.
It's a really large sketch so I'm paring it down to include it later today.
Unfortunately the dog pulled my scope off the bench and broke so I'm a bit blind this week.
any thoughts would be appreciated, thanks
Both devices work fine in a loopback test (connecting the TX to the RX.) and the teensy works fine in loopback with serial1 and serial2. When I have the issue is when I connect the 2 devices together. The both share the same power and ground.
If I connect the TX and RX pins on serial2 to the esp pins, the esp will not receive any data but can send. Same situation on serial1. If I connect the teensy TX on serial2 and RX on serial1 it works fine. basically I can not send and receive on the same teensy port if it attached to the esp device.
some details:
all serial at 19.2k
data packets about 50 chars, once every second
teensy 3.5, ide1.87 teensyduino 1.48
heltec htit w2866 for the esp board
the wire length for the serial connections is 6 inches.
I have SPI included as well as modbusmaster (tied to serial3)
I've been using serial comms on teensy's for years and never really seen anything like this, although admittedly I usually put a max232 between them.
It's a really large sketch so I'm paring it down to include it later today.
Unfortunately the dog pulled my scope off the bench and broke so I'm a bit blind this week.
any thoughts would be appreciated, thanks