An affordable, inexpensive and “cheap” Saleae clone could save your day (really).
You could find it for less than U$ 10:
I was implementing a NuttX driver for BMP180 over I2C, but was failing to get it working and it was difficult to discover what was going on.
I decided to test my cheap Saleae clone for the first time. The Sigrok tool installation from source code is explained here:
Then compared my driver command:
against Adrafruit BMP085/BMP180 commands:
Imediately I noticed I forgot to write the register address that I need to read before issuing the read command.
Just an I2C_WRITE before a I2C_READ fixed the issue!
Related: How to use sigrok to measure real-time signal latency http://blog.savoirfairelinux.com/en/2014/logic-analyzer-visualize-latency-with-sigrok-and-matplotlib/
Update: You need to copy the firmware to Sigrok work:
cp fx2lafw-saleae-logic.fw /usr/local/share/sigrok-firmware/fx2lafw-saleae-logic.fw
I got the firmware from sigrok-firmware-fx2lafw-bin-0.1.3.tar.gz