Alfat 2 I2C_busy signal stuck high


I am currently having trouble with the Alfat 2.

First, I read the banner from the Alfat chip.

Then I mount the USB device as “U0:”

I proceed to append to a nonexistent file. It is then created in the process.

After sending about 2100 bytes to the Alfat the I2C_busy signal goes high and stays high. In the firmware I have a loop that waits until the I2C_busy line goes low before I send my data. I have waited for several minutes but it remains high.

In this application I was previously using the Alfat 1 but after the discontinuation I switched to the Alfat 2. That is when this problem began to appear.

This is on a custom board, but I have verified that electrically it is sound.

What exactly is the procedure when the I2C_busy line goes high? Have I missed something in the datasheet about the I2C protocol?


@ t11230 -

it is not happened in ALFAT1 but happened in ALFAT 2?, does that what you mean?

The busy pin does only go high when the buffer is bigger than 4K OR read/write data to media.