USB section of an audio interface

Hi,
My TASCAM US-122mkII stopped installing driver. I tried with different four computers with three cables. So I think device has fault.

Opened the interface and found a ISP1583 USB chip which is controlled by ATMEGA162. Do you think if I got a new ISP1583 chip and replaced, then can I fix the interface problem?

Hi Willen,

have you tried resoldering the USB connector and checked continuity between that and the pins on the 1583? The IC may have failed, but I'd think a mechanical fault with connections is more likely?

rjenkinsgb said:

Hi Willen,

have you tried resoldering the USB connector and checked continuity between that and the pins on the 1583? The IC may have failed, but I'd think a mechanical fault with connections is more likely?

Click to expand...

Hi,
Did this test. The device is getting power from the USB so it is glowing red LED (which glows when we plug the device without installing driver). It means two power pins are ok. I tested the continuty of two data pins from cable to the ISP1583. So data input path from connector to the USB chip is also fine (got continuty). It has pretty strong PCB and design.

The ISP1583 is being controlled by Atmega162 chip. I wish problem is not under the Atmega chip. Maybe it gas secret firmware to which we never get to fix this microcontroller. The TASCAM download page has two types of software
1. Driver
2. Firmware update

I don't know what is 2nd option. Does this mean we can also load firmware inside the ATMEGA162 chip?

Willen said:

I don't know what is 2nd option. Does this mean we can also load firmware inside the ATMEGA162 chip?

Click to expand...

Yes, the firmware updater should reload the atmega CPU - but it may only work on one that has already been programmed, so has the correct loader code?

I don't know if those CPUs have a factory-installed USB loader.

It may be worth trying to reload the firmware in yours anyway, just in case something has got corrupted.
It would also show if the USB section is working?

rjenkinsgb said:

Yes, the firmware updater should reload the atmega CPU - but it may only work on one that has already been programmed, so has the correct loader code?

I don't know if those CPUs have a factory-installed USB loader.

It may be worth trying to reload the firmware in yours anyway, just in case something has got corrupted.
It would also show if the USB section is working?

Click to expand...

There is FirmwareUpdater.exe file in TASCAM, maybe it loads firmware through USB, But my USB section is dead. Device manager shows nothing when it is connected.

Near the Atmega162 chip there is a 6 pin PCB header marked as J4 and 1 to 6 pin as pin count. Maybe this is to load firmware seperatly. But we do not have that firmware file (like HEX file).

OK.. I was hoping the firmware updater worked directly to the USB system and bypassed the audio driver.

Are you getting a full 5V in the US-122 when it's connected? If it's low, 4.5 or less, that may prevent it working?

rjenkinsgb said:

OK.. I was hoping the firmware updater worked directly to the USB system and bypassed the audio driver.

Are you getting a full 5V in the US-122 when it's connected? If it's low, 4.5 or less, that may prevent it working?

Click to expand...

Hi, I tested the voltage on the board after the connector, it is 4.91V. Looks normal as before.

That's sad... Something has definitely failed catastrophically.
It could be the USB interface, but there is no easy way of knowing other than swapping the IC and seeing if it starts working again.