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R12 · CONNECTION OVERVIEW · 29 SEP 2026

One 19-pin link.

Presentation ↗Full KiCad ↗

Recording goes to XEM.

Commands return to the custom FPGA.

Pin sheet ↗PDF ↗

Two recording differential pairs, contacts 3/5 and 6/8, go from the custom FPGA through interposer J201 to XEM GTY Bank 226. Commands on contacts 12/14 travel back. Contacts 9/11 are Reserved; contacts 4/7/10/13/16 are ground. — Arrows show signal direction. Scroll diagram ↔

Choose the programming source.

Probe by default. XEM uses a level translator.

JTAG sheet ↗PDF ↗

A recovery probe bypasses the translator. XEM 1.2 V fabric GPIO uses a 1.2 to 1.8 V translator. Three source selectors choose TMS contact 2, TDI 15 and TCK 17 to the target. TDO contact 18 returns to the probe input and, through the translator, the XEM receiver. Target VTREF contact 1 supplies the translator B-side bias and the probe reference. ARM defaults open; XEM bridge gateware is pending. — VTREF supplies translator bias; the host never drives that rail. XEM bridge gateware and ARM enable remain pending. Scroll diagram ↔

One source, two power paths.

XEM feed and cable protection are separate.

Power sheet ↗PDF ↗

Return: GND 4 / 7 / 10 / 13 / 16. Power branch and remote regulators remain under review. Scroll diagram ↔

Schematic overview · routing in progressJTAG and ground routing remain open.