参数资料
型号: MC68HC05V7CB
厂商: FREESCALE SEMICONDUCTOR INC
元件分类: 微控制器/微处理器
英文描述: 8-BIT, MROM, 2.1 MHz, MICROCONTROLLER, PDIP56
封装: SDIP-56
文件页数: 162/170页
文件大小: 980K
代理商: MC68HC05V7CB
SECTION 12: CORE TIMER
MOTOROLA
Page 77
MC68HC05V7 Specification Rev. 1.0
12.1.6
RTFC - Real Time Interrupt Flag Clear
When a “1” is written to this bit, RTIF is cleared. Writing a “0” has no effect on the RTIF bit.
This bit always reads as zero.
12.1.7
RT1:RT0 - Real Time Interrupt Rate Select
These two bits select one of four taps from the Real Time Interrupt circuit. Table 12-1 shows
the available interrupt rates with a 2.1 and 1.05MHz bus clock. Reset sets these two bits
which selects the lowest periodic rate and gives the maximum time in which to alter these
bits if necessary. Care should be taken when altering RT0 and RT1 if the time-out period
is imminent or uncertain. If the selected tap is modified during a cycle in which the counter
is switching, an RTIF could be missed or an additional one could be generated. To avoid
problems, the COP should be cleared before changing RTI taps.
Table 12-1: RTI and COP Rates at 2.1 MHz
12.2
COMPUTER OPERATING PROPERLY (COP) RESET
The COP watchdog timer function is implemented on this device by using the output of the
RTI circuit and further dividing it by eight. The minimum COP reset rates are listed in Table
12-1. If the COP circuit times out, an internal reset is generated and the normal reset vector
is fetched. Preventing a COP time-out, or clearing the COP, is accomplished by writing a
“0” to bit 0 of address $3FF0. When the COP is cleared, only the final divide by eight stage
(output of the RTI) is cleared.
If the COP watchdog timer is allowed to time-out, an internal reset is generated to reset the
MCU. In addition the RESET pin will be pulled low for a minimum of 3 E Clock cycle for
emulation purposes. During a chip reset (regardless of the source), the entire Core Timer
counter chain is cleared.
The COP will remain enabled after execution of the WAIT instruction and all associated
operations apply. If the STOP instruction is disabled, execution of STOP instruction will
cause an internal reset.
This COP’s objective is to make it impossible for this part to become “stuck” or “locked-up”
and to be sure the COP is able to “rescue” the part from any situation where it might entrap
itself in an abnormal or unintended behavior. This function is a mask option.
11
RT1:RT0
MIN. COP RATES
00
01
10
214/E
RTI RATE
211/E
212/E
213/E
15.60 ms
1.95 ms
3.90 ms
7.80 ms
0.97 ms
1.95 ms
3.90 ms
109.23ms
13.65ms
27.31ms
54.61ms
54.61 ms
6.83 ms
13.65 ms
27.31 ms
(217-214)/E
(214-211)/E
(215-212)/E
(216-213)/E
1.05 MHz
2.1 MHz
1.05 MHz
2.1 MHz
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
..
.
相关PDF资料
PDF描述
MC68HC711EA9VFS3 8-BIT, UVPROM, 3 MHz, MICROCONTROLLER, CQCC52
MPC7400RX350TX 32-BIT, 350 MHz, RISC PROCESSOR, CBGA360
MPC8250ACVRLHDX 32-BIT, 250 MHz, RISC PROCESSOR, PBGA516
MC68HC11L1VFU2 8-BIT, 2 MHz, MICROCONTROLLER, PQFP64
MC68HC08JL3CP 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PDIP28
相关代理商/技术参数
参数描述
MC68HC05X16 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:High-density complementary metal oxide semiconductor HCMOS) microcontroller unit
MC68HC05X32 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:High-density complementary metal oxide semiconductor HCMOS) microcontroller unit
MC68HC05X4 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:HCMOS Microcontroller Unit
MC68HC05X4CDW 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:HCMOS Microcontroller Unit
MC68HC05X4DW 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:HCMOS Microcontroller Unit