HC705RC16GRSSLASHD datasheet(61/120 Pages) NXP

61 / 120 page

Core Timer

Core Timer Control and Status Register

MC68HC705RC16 — Rev. 3.0

General Release Specification

Core Timer

8.3 Core Timer Control and Status Register

The CTCSR contains the timer interrupt flag, the timer interrupt enable

bits, and the real-time interrupt rate select bits. Figure 8-2 shows the

value of each bit in the CTCSR when coming out of reset.

CTOF — Core Timer Overflow

CTOF is a read-only status bit set when the 8-bit ripple counter rolls

over from $FF to $00. Clearing the CTOF is done by writing a one to

TOFC. Writing to this bit has no effect. Reset clears CTOF.

RTIF — Real-Time Interrupt Flag

The real-time interrupt circuit consists of a 3-stage divider and a

one-of-four selector. The clock frequency that drives the RTI circuit is

E/212 (or E

÷ 4096 with three additional divider stages, giving a

maximum interrupt period of 16 milliseconds at a bus rate of 2.024

MHz. RTIF is a clearable, read-only status bit and is set when the

output of the chosen (one-of-four selection) stage goes active.

Clearing the RTIF is done by writing a one to RTFC. Writing has no

effect on this bit. Reset clears RTIF.

TOFE — Timer Overflow Enable

When this bit is set, a CPU interrupt request is generated when the

CTOF bit is set. Reset clears this bit.

RTIE — Real-Time Interrupt Enable

When this bit is set, a CPU interrupt request is generated when the

RTIF bit is set. Reset clears this bit.

Address:

$08

Read:

CTOF

RTIF

TOFE

RTIE

RT1

RT0

Write:

TOFC

RTFC

Reset:

00000011

= Unimplemented

Figure 8-2. Core Timer Control and Status Register (CTCSR)

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

HC705RC16GRS/D Datasheet(PDF) 61 Page - NXP Semiconductors

HC705RC16GRS/D Datasheet(HTML) 61 Page - NXP Semiconductors

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

Datasheet Download

Link URL