break-out board for AMR modem riser
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
Updated by laforge over 2 years ago
- Status changed from New to In Progress
- % Done changed from 0 to 80
design files committed in https://git.osmocom.org/osmo-small-hardware/commit/?id=b76fb674e1174786b7d086adab45c38dbeb2b1a1 and 3 prototypes ordered from aisler.
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.
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).
- 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.