Power two LED with jetson tx2 i2c

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
1

I have two LED devices Amazon.com and
https://www.amazon.com/Adafruit-Bicolor-Square-Matrix-Backpack/dp/B00OKJFASE/ref=sr_1_1?keywords=Adafruit+Bicolor+LED+Square+Pixel+Matrix+with+I2C+Backpack&qid=1567022738&s=gateway&sr=8-1

And would like to use Jetson Tx2 i2c cto drive it. I wired the 7 Seg LED to Bus 1

GND J21-6 → LED Backpack (GND)
VCC J21-2 → LED Backpack (VCC – 5V)
SDA J21-3 → LED Backpack (SDA)
SCL J21-5 → LED Backpack (SCL)

And I wired the 8x8 LED matrix to Bus 0

GND J21-30 → LED Backpack (GND)
VCC J21-4 → LED Backpack (VCC – 5V)
SDA J21-27 → LED Backpack (SDA)
SCL J21-28 → LED Backpack (SCL)

Inside my ros node, I used the driver code from here GitHub - jetsonhacks/JHLEDBackpack: I2C interface for Adafruit LED Backpack for 7 segment display I create two HT16K33, one used bus 1, the other used bus 0. Both use kI2CAddress 0x70.

This way, I found that I could run the two devices separately, but I could not run them at the same time.

Would you please let me know why? I can not sure if both can use the same kI2CAddress 0x70.

2

Hi AutoCar,

Could you try to use i2cdump or i2cset on bus 0 and bus 1 with both addr = 0x70 and see if it can run simultaneously?

3

I am not sure how to run both simultaneously, could you share the command?

4

When I run i2cdump, the output is like below:

nvidia@tegra-ubuntu:~/racecar-ws/src/coneslam/config$ i2cdump 0 0x70
No size specified (using byte-data access)
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-0, address 0x70, mode byte
Continue? [Y/n] y
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 00 1f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 .?..
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
nvidia@tegra-ubuntu:~/racecar-ws/src/coneslam/config$ i2cdump 1 0x70
No size specified (using byte-data access)
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-1, address 0x70, mode byte
Continue? [Y/n] y
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 00 00 00 00 00 00 00 00 3f 00 00 00 00 00 00 00 …?..
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …

5

Could you check your app and see how it uses the i2c tool? Looks like it can read simultanenously.

According to the readme, that app also uses i2c-tool (i2cdump/i2cset).