RX63N CPU

R5F563NFDDFP
RX63NF
635AZ00

100-pin LQFP

https://www.renesas.com/en-us/doc/products/mpumcu/doc/rx_family/r01ds0098ej0180_rx63n631.pdf
https://www.renesas.com/en-us/doc/products/mpumcu/doc/rx_family/r01uh0041ej0180_rx63n631.pdf?key=c660422bdfa54810799fac22849c6fd0
https://www.renesas.com/en-us/document/hw-manual?hwLayerShowFlg=false&prdLayerId=null&layerName=null&coronrService=null&hwDocUrl=%2Fen-us%2Fdoc%2Fproducts%2Fmpumcu%2Fdoc%2Frx_family%2Fr01uh0041ej0180_rx63n631.pdf&hashKey=acef4b11f6502fc88172da90c6191f84
https://www.renesas.com/en-us/doc/products/mpumcu/doc/rx_family/r01uh0041ej0180_rx63n631.pdf?key=acef4b11f6502fc88172da90c6191f84

Schematics with RX63N CPU
https://webpages.uncc.edu/~jmconrad/ECGR4101-2013-08/notes/YRDKRX63N_SCH_3.pdf

125kHz LOCO frequency
12MHz XTAL frequency

Markings
T12M
1629

Size of crystal
4×2.5mm

Removed and checked without 1MOhm loading crystal (which may now be broken after soldering lead to EXTAL side)

Will try to bodge in this crystal oscillator
CFPS-69 12MHz 3.3v +-5%
https://www.elfa.se/sv/oscillator-cfps-69-12-mhz-iqd-lfspxo009585/p/17457591
https://www.elfa.se/Web/Downloads/_t/ds/cfps-69_eng_tds.pdf

This worked fine, taking 3.3V from the CPU pins right next to the EXTAL pin where the output of the oscillator has been connected to