NEC UPD703116 User Manual page 317

(b) Up/down count operation in UDC mode
TM1n up/down count judgment in the UDC mode is determined based on the phase difference of the
TIUD1n and TCUD1n pin inputs according to the PRM1n register setting.
(i) Mode 1 (PRM1n register's PRM12 bit = 1, PRM11 bit = 0, PRM10 bit = 0)
In mode 1, the following count operations are performed based on the level of the TCUD1n pin upon
detection of the valid edge of the TIUD1n pin.
• TM1n down-count operation when TCUD1n pin = high level
• TM1n up-count operation when TCUD1n pin = low level
Figure 9-51. Mode 1 (When Rising Edge Is Specified as Valid Edge of TIUD1n Pin)
TIUD1n
TCUD1n
TM1n
Remark n = 0, 1
CHAPTER 9 TIMER/COUNTER FUNCTION
0007H 0006H 0005H
Down count
User's Manual U14492EJ5V0UD
0004H 0005H 0006H
Up count
0007H
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