I recently purchased the Sparkfun Redboard, LTE CAT-m Shield, and Ethernet Sheild. I would like to connect all 3 boards together. However, I the Redboard and the LTE CAT-m Shield seems not to be compatible. When connected via the pin headers (Readboard to LTE Shield) I get the following arduino errors when uploading the sketch:
nary sketch size: 1,052 bytes (of a 32,256 byte maximum)
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x20
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x20
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x20
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x20
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x30
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x20
I do not have these errors with just the Redboard connected, or with the Ethernet shield.
I have tested the pin header for shorts with a continuity meter and found no shorts.
Is the LTE Shield not compatible with the Redboard?
Can you try programming the RedBoard without the shield, unplug from computer/power source, mount shields, then repower your unit? This will help to see if the RedBoard is solely having issues.
Also: common things to check would be the serial port, target board, programmer profile, and the USB cable itself. Sometimes the cable might not make a great connection for the data lines.
Did you read above??? Of course, I can program it without the shield. Read above everything I did. It’s the Sheild CATM doesn’t work with the redboard.
yes it’s the basic Arduino Blink Sketch. As mentioned before, the programmer works fine without the CATM Shield. Then the programmer times out with the Shield. Hence, it is not a code issue, it’s some electrical interference caused by the CATM shield on the programmer. Have you connected the CATM shield to the Redboard to verify this issue?
I have connected them. I ran a blank sketch, blink, and example 00_Register_Operator from our LTE library. All three uploaded without errors. Can you provide pictures of your setup?
Maybe… let’s try something different. remove the shield and try to insert it again, but bend TX and RX pins a little so they do not make contact when you re-insert.
The RX/TX pins go directly to the UART switch. Can you check the switch with an OHM meter. The TX and RX should measure high ( mega ohm or more) when measuring against GND when the switch in SOFT.
Not really. the communication CAN happen with the TX/TX pin 0 an 1 (HARD UART) or with softserial over pin 8 and 9 ( UART SOFT). This softserial approach is the easiest and default. BUT
your switch must switch correctly (and I have still concerns there)
I started working recently with the LTE CAT-M and in the first sketch it tries to communicate with the board on 9600. That did not work as my board worked on 115200. 115K is a very high speed for softserial to work stable. I connected the board to a Mega, serial1, and I am figuring out whether the speed can be set to 9600.