Count Clock Selection - NEC V850E/MS1 UPD703100 User Manual

CHAPTER 9 TIMER/COUNTER FUNCTION (REAL-TIME PULSE UNIT)

9.4.2 Count clock selection

The count clock input to Timer 1 is either internal or external, and can be selected by the ETI1n bit in the TMC1n
register (n = 0 to 5).
Caution Do not change the count clock during timer operation.
(1) Internal count clock (ETI1n bit = 0)
An internal count clock can be selected from among 6 possible clock rates, φ /2, φ /4, φ /8, φ /16, φ /32, or φ /64,
by the setting of the PRS1n1, PRS1n0, and PRM1n1 bits of the TMC1n register.
Remark
(2) External count clock (ETI1n bit = 1)
This counts the signals input to the TI1n pin. At this time, Timer 1 can be operated as an event counter.
The TI1n active edge can be set by the TES1n1 and TES1n0 bits of the TUM1n register.
Remark
PRS1n1 PRS1n0
0 0
0 0
0 1
0 1
1 0
1 0
1 1
1 1
n = 0 to 5
TES1n1 TES1n0
0 0 Rising edge
0 1 Falling edge
1 0 RFU (reserved)
1 1 Both the rising and falling edges
n = 0 to 5
User's Manual U12688EJ4V0UM00
PRM1n1 Internal Count Clock
φ /2
0
φ /4
1
φ /8
0
φ /16
1
φ /16
0
φ /32
1
φ /32
0
φ /64
1
Active Edge
263