M16C1N Datasheet, PDF (74/238 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/10 SERIES

M16C/1N Group
10. Interrupt
10.3 CNTR0 Interrupt
A CNTR0 interrupt is generated from the selected edge polarity, a rising or a falling edge, of the CNTR0
input signal. The edge polarity is selected using the CNTR0 polarity select bit (bit 2 at address 008B16).
When using the CNTR0 interrupt, the port P17 direction register should be set to input.
When the pulse output mode of timer X is selected, the CNTR0 pin functions as a pulse output pin. In this
case, a CNTR0 interrupt occurs by a falling or rising edge output from the CNTR0 pin. The port P17
direction register should else be set to input at this time.
Figure 10.12 shows the timer X mode register.
Timer X mode register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
TXMR
Address
008B16
When reset
0016
Bit symbol
Bit name
Function
RW
TXMOD0 Operation mode
select bit 0, 1
b1 b0
0 0 : Timer mode or
pulse period measurement mode
RW
(Note 2) _{0 1 : Pulse output mode (Note 1)}
TXMOD1
1 0 : Event counter mode
RW
1 1 : Pulse width measurement mode
R0EDG
CNTR0 polarity
0 : Rising edge
switching bit (Note 2) 1 : Falling edge
RW
TXS
Timer X count
start flag
0 : Stops counting
1 : Starts counting
RW
TXOCNT
P30/TXOUT
select bit
Function varies with each operation mode
RW
TXMOD2 Operation mode
select bit 2
0 : Except in pulse period measurement mode
1 : Pulse period measurement mode
RW
TXEDG
Effectual edge
Function varies with each operation mode
reception flag (Note 3)
RW
TXUND
Timer X under flow Function varies with each operation mode
flag (Note 3)
RW
Note 1: In the pulse output mode, the direction register of port P17 should be set to input.
Note 2: This bit should rewrite with inhibiting the CNTR0 interrupt. To use all interrupt, enable an interrupt after the CNTR0
interrupt request bit is cleared with the MOV instruction.
Note 3: Nothing is assigned to the pod probe for M16C/1N group (M301N2T-PRB).
Figure 10.12 Timer X mode register
Rev.1.00 Oct 20, 2004 page 62 of 222
REJ09B0007-0100Z