HD64F2168 Datasheet, PDF (375/874 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

12.9.6 Mode Setting with Cascaded Connection
If the 16-bit count mode and compare-match count mode are set simultaneously, the input clock
pulses for TCNT_0 and TCNT_1 are not generated, and thus the counters will stop operating.
Simultaneous setting of these two modes should therefore be avoided.
Rev. 3.00, 03/04, page 335 of 830