M16CSLASH1N datasheet(90/238 Pages) RENESAS

90 / 238 page

Rev.1.00

Oct 20, 2004

page 78 of 222

M16C/1N Group

12. Timers

REJ09B0007-0100Z

b5 b4

Timer X mode register

TXMOD0

TXMOD1

Operation mode

select bit 0, 1

(Note 1)

1 1 : Pulse width measurement mode

R0EDG

CNTR0 polarity

switching bit (Note 1)

0 : Measures "L" level width (Interrupt at rising edge)

1 : Measures "H" level width (Interrupt at falling edge)

TXS

Timer X count

start flag

0 : Stops counting

1 : Starts counting

TXMOD2

0 : Set to "0" in pulse width measurement mode

TXOCNT

0 : Set to "0" in pulse width measurement mode

Symbol

TXMR

Address

008B16

When reset

0016

Function

Bit name

Bit symbol

b1 b0

P30/TXOUT

select bit

Operation mode

select bit 2

TXEDG

Effectual edge

reception flag

TXUND

Timer X under

flow flag

Invalid in pulse width measurement mode.

When write, set "0". When read, this contents

is indeterminate.

Invalid in pulse width measurement mode.

When write, set "0". When read, this contents

is indeterminate.

Note 1: This bit should rewrite with inhibiting the CNTR0 interrupt. When using the interrupt, the interrupt must be enabled

after clearing the CNTR0 interrupt request bit to "0" using a MOV instruction.

Item

Specification

Count source

f1, f8, f32, fC32

Count operation

• Down count

• Continuously counts the selected signal only when the measurement pulse is "H" level,

or conversely only "L" level.

• When the timer underflows, it reloads the reload register contents before continuing

counting

Count start condition

Count start flag is set (=1)

Count stop condition

Count start flag is reset (=0)

Interrupt request generation timing • When Timer X underflows [Timer X interruption]

• Rising (R0EDG=0) or falling (R0EDG=1) of CNTR0 input [CNTR0 interruption]

CNTR0 pin function

Measurement pulse input

TXOUT pin function

Programmable I/O port

Read from timer

Count value can be read out by reading Timer X register.

Same applies to Prescaler X register.

Write to timer

When a value is written to Timer X register, it is written to both reload register and counter.

Same applies to Prescaler X register.

Select function

• CNTR0 polarity switching function

The measurement pulse input can be selected to be "H" level width or "L" level width by

software.

Table 12.6 Specifications of pulse width measurement mode

12.2.4 Pulse Width Measurement Mode

In this mode, the timer measures the pulse width of an external signal fed to CNTR0 pin.

(See Table 12.6) Figure 12.9 shows the Timer X mode register in pulse width measurement mode.

Figure 12.10 shows an operation example in pulse width measurement mode.

Figure 12.9 Timer X mode register in pulse width measurement mode

M16C/1N датащи(PDF) 90 Page - Renesas Technology Corp

M16C/1N датащи(HTML) 90 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL