GD32VF103 User Manual
258
Bits
Fields
Descriptions
15
ETP
External trigger polarity
This bit specifies the polarity of ETI signal
0: ETI is active at high level or rising edge.
1: ETI is active at low level or falling edge.
14
SMC1
Part of SMC for enable External clock mode1.
In external clock mode 1, the counter is clocked by any active edge on the ETIFP
signal.
0: External clock mode 1 disabled
1: External clock mode 1 enabled.
It is possible to simultaneously use external clock mode 1 with the restart mode,
pause mode or event mode. But the TRGS bits must not be 3’b111 in this case.
The external clock input will be ETIFP if external clock mode 0 and external clock
mode 1 are enabled at the same time.
Note: External clock mode 0 enable is in this register’s SMC bit-filed.
13:12
ETPSC[1:0]
External trigger prescaler
The frequency of external trigger signal ETIFP must not be at higher than 1/4 of
TIMER_CK frequency. When the external trigger signal is a fast clock, the prescaler
can be enabled to reduce ETIFP frequency.
00: Prescaler disable
01: ETIFP frequency will be divided by 2
10: ETIFP frequency will be divided by 4
11: ETIFP frequency will be divided by 8
11:8
ETFC[3:0]
External trigger filter control
An event counter is used in the digital filter, in which a transition on the output occurs
after N input events. This bit-field specifies the frequency used to sample ETIFP
signal and the length of the digital filter applied to ETIFP.
0000: Filter disable. f
SAMP
= f
DTS
, N=1.
0001: f
SAMP
= f
TIMER_CK
, N=2.
0010: f
SAMP
= f
TIMER_CK
, N=4.
0011: f
SAMP
= f
TIMER_CK
, N=8.
0100: f
SAMP
=f
DTS
/2, N=6.
0101: f
SAMP
=f
DTS
/2, N=8.
0110: f
SAMP
=f
DTS
/4, N=6.
0111: f
SAMP
=f
DTS
/4, N=8.
1000: f
SAMP
=f
DTS
/8, N=6.
1001: f
SAMP
=f
DTS
/8, N=8.
1010: f
SAMP
=f
DTS
/16, N=5.
1011: f
SAMP
=f
DTS
/16, N=6.
1100: f
SAMP
=f
DTS
/16, N=8.
1101: f
SAMP
=f
DTS
/32, N=5.
1110: f
SAMP
=f
DTS
/32, N=6.