Table of Contents
Advertisement
Note on Rewriting Port Mode Registers: When a port mode register setting is modified to
enable or disable the input capture function or input capture noise canceling function, note the
following points.
• Switching the function of the input capture pin
When the function of the input capture pin is switched by modifying port mode register 1
(PMR1) bit 3 (the TMIG bit), an input capture edge may be recognized even though no valid
signal edge has been input. This occurs under the conditions listed in table 9.12.
Table 9.12 False Input Capture Edges Generating by Switching of Input Capture Pin
Function
Input Capture Edge
Rising edge recognized
Falling edge recognized
Note: When pin P1
• Switching the input capture noise canceling function
When modifying port mode register 2 (PMR2) bit 4 (the NCS bit) to enable or disable the input
capture noise canceling function, first clear the TMIG bit to 0. Otherwise an input capture edge
may be recognized even though no valid signal edge has been input. This occurs under the
conditions listed in table 9.13.
Table 9.13 False Input Capture Edges Generating by Switching of Noise Canceling
Function
Input Capture Edge
Rising edge recognized
Falling edge recognized
194
Conditions
TMIG pin level is high, and TMIG bit is changed from 0 to 1
TMIG pin level is high and NCS bit is changed from 0 to 1, then TMIG
bit is changed from 0 to 1 before noise canceller circuit completes five
samples
TMIG pin level is high, and TMIG bit is changed from 1 to 0
TMIG pin level is low and NCS bit is changed from 0 to 1, then TMIG
bit is changed from 0 to 1 before noise canceller circuit completes five
samples
TMIG pin level is high and NCS bit is changed from 0 to 1, then TMIG
bit is changed from 1 to 0 before noise canceller circuit completes five
samples
is not used for input capture, the input capture signal input to timer G is low.
3
Conditions
TMIG bit is set to 1 and TMIG pin level changes from low to high, then
NCS bit is changed from 1 to 0 before noise canceller circuit completes
five samples
TMIG bit is set to 1 and TMIG pin level changes from high to low, then
NCS bit is changed from 1 to 0 before noise canceller circuit completes
five samples
Advertisement
Table of Contents
