Hi
HC908JK is too old. It's hard to find C demo code for this chip exactly.
But you can refer AN2504SW and AN2948SW.
8-bit General Purpose JK and JL MCUs|NXP
AN2504SW is for HC908JL, you can also use it for HC908JK
EY, QY of AN2948SW are both HC08 core as CH908JK, You can refer it to develop HC908JK too.
Have a great day,
Jennie Zhang
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