Feature #5294


break-out board for AMR modem riser

Added by laforge over 2 years ago. Updated 6 months ago.

Target version:
Start date:
Due date:
% Done:


Spec Reference:


It would be great to have a break-out board for the AMR_Modem_Riser so we can try to hook them up to a microcontroller emulating the AC-link interface (e.g. using SAM3S SSC).

The break-out board should have:
  • mechanical connector for AMR card
  • expose all analog and digital signals to 2.54mm headers
  • DC input for 5V (barrel? USB Vbus?)
    • jumper to +5VD
    • jumper to +5Vdual
  • onboard 5V -> 3.3V LDO
    • jumper to +3.3Vdual
    • jumper to +3.3VD
  • no +/- 12V on-board power supply, but at least some way to supply it externally
  • test points for attaching [scope, logic analyzer] probes to AC-link signals


amr-breakout.png View amr-breakout.png 70 KB laforge, 11/17/2021 06:16 PM
amr_breakout_prototype.jpg View amr_breakout_prototype.jpg 812 KB laforge, 12/28/2021 07:25 AM
Actions #1

Updated by laforge over 2 years ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 80

design files committed in and 3 prototypes ordered from aisler.

Actions #3

Updated by laforge about 2 years ago

  • Status changed from In Progress to Stalled

the first 3 break-out boards have been assembled about a month ago. All I tested so far was whether the DC power appears where expected, and that the on-board LDO works. Further evaluation to be done by tnt who has kindly offered to look at implementing AC97 in an iCE40 FPGA.

Actions #4

Updated by tnt about 2 years ago

I did verify I could get the AMR board to send me a master clock when you configure it to be the master codec, you get teh expected 12.288 MHz clock once you've gone through the reset process.

I also started on the AC97 HDL interface for it (purely in sim for now, I'm planning to continue this during the week).

I opened a couple issues ( #5369 and #5375 ) in the small hardware repo about it btw.

Actions #5

Updated by laforge about 2 years ago

picture of assembled board:

Actions #6

Updated by laforge 6 months ago

  • Status changed from Stalled to Resolved
  • % Done changed from 80 to 100

The break-out board has been verified by tnt at CCC Camp 2023, where he successfully transmitted a Fax (using spandsp) via pulseaudio - alsa - usb-audio - iCE40 FPGA - AMR riser. Closing.


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