I am trying to get an MP-954 serial card working on a RB411UAHR and am having some issues. Characters are transferred over the cards serial port, but they are garbled, almost like baud rates are off.

The same behavior is present in ROS and OpenWrt. Interestingly enough, I managed to get the same card working on a RSPRO, which is the same basic AR7161 platform, using OpenWRT.

Since the issue is present only on the RB411, and under both ROS and OpenWRT, it would seem there is some quirk with the RB411's implementation of the AR7161.

I'm sure this falls out of the "supported hardware/software" realm, but any insight into the workings of the PCI bus on the RB411 might help me solve this dilemma.


http://www.commell.com.tw/product/Perip ... MP-954.HTM

try to play with the flow control settings and different baud rates.

Slower baud rates seem to be better in terms of character by character transfer, but its still not right. When the card is in the RSPRO, all baud rates function.

One other observation: if i plug 2 of the MP-954 ports together via a null modem, i get a flood of gibberish on on port (even though i didnt send any characters)

My current theory is that the clock crystal on the MP-954 is not running at the right frequency. Maybe due to over/under voltage on the PCI bus??? This is all a bit out of my area of expertise.

A clarification on the above statement:

At low baud rates ( < 115200) characters are transferred correctly to the MP-954, but characters sent from the MP-954 are still garbled. I don't know if it sort-of working in one direction, but not the other sheds any light on the issue. Again, it works fine on a RSPRO, but the same behavior is present on the 411 under ROS and OpenWrt.


Terminal running on the 411UAHR attached to ttyS1
- Characters received here are displayed properly
- Characters typed here come out garbled on the other end


~NULL MODEM~


Terminal on an external PC
- Characters typed here display properly at the other end
- Characters received here are garbled