68HC705JB4 datasheet(55/134 Pages) FREESCALE

55 / 134 page

February 24, 1999

GENERAL RELEASE SPECIFICATION

MC68HC05JB4

MULTI-FUNCTION TIMER

MOTOROLA

REV 2

8-3

8.3

MFT REGISTERS

8.3.1 Timer Counter Register (TCNT) $09

The Timer Counter Register is a read-only register which contains the current

value of the 8-bit ripple counter at the beginning of the timer chain. This counter is

clocked at fOP÷4 and can be used for various functions including a software input

capture. Extended time periods can be attained using the TOF function to incre-

ment a temporary RAM storage location thereby simulating a 16-bit (or more)

counter. The value of each bit of the TCNT is shown in Figure 8-2. This register is

cleared by reset.

Figure 8-2. Timer Counter Register

8.3.2 Timer Control/Status Register (TCSR) $08

The TCSR contains the timer interrupt ﬂag bits, the timer interrupt enable bits, and

the real time interrupt rate select bits. Bit 2 and bit 3 are write-only bits which will

read as logical zeros. Figure 8-3 shows the value of each bit in the TCSR follow-

ing reset.

Figure 8-3. Timer Control/Status Register (TCSR)

TOF - Timer Overﬂow Flag

The TOF is a read-only ﬂag bit.

1 =

Set when the 8-bit ripple counter rolls over from $FF to $00. A

TIMER Interrupt request will be generated if TOFE is also set.

0 =

Reset by writing a logical one to the TOF acknowledge bit, TOFR.

Writing to the TOF ﬂag bit has no effect on its value. This bit is

cleared by reset.

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

TCNT

TMR7

TMR6

TMR5

TMR4

TMR3

TMR2

TMR1

TMR0

$0009

reset:

00000000

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

TCSR

TOF

RTIF

TOFE

RTIE

RT1

RT0

$0008

TOFR

RTIFR

reset:

00000011

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

68HC705JB4 bảng dữ liệu(PDF) 55 Page - Freescale Semiconductor, Inc

68HC705JB4 bảng dữ liệu(HTML) 55 Page - Freescale Semiconductor, Inc

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

bảng dữ liệu tải về

Link URL