参数资料
型号: MCHC11F1VFNE3
厂商: Freescale Semiconductor
文件页数: 149/158页
文件大小: 0K
描述: MCU 8BIT 1KRAM 512EE 68-PLCC
标准包装: 18
系列: HC11
核心处理器: HC11
芯体尺寸: 8-位
速度: 3MHz
连通性: SCI,SPI
外围设备: POR,WDT
输入/输出数: 30
程序存储器类型: ROMless
EEPROM 大小: 512 x 8
RAM 容量: 1K x 8
电压 - 电源 (Vcc/Vdd): 4.75 V ~ 5.25 V
数据转换器: A/D 8x8b
振荡器型: 内部
工作温度: -40°C ~ 105°C
封装/外壳: 68-LCC(J 形引线)
包装: 管件
SERIAL COMMUNICATIONS INTERFACE
MC68HC11F1
7-4
TECHNICAL DATA
7.4 Wakeup Feature
The wakeup feature reduces SCI service overhead in multiple receiver systems. Soft-
ware for each receiver evaluates the first character of each message. The receiver is
placed in wakeup mode by writing a one to the RWU bit in the SCCR2 register. While
RWU is one, all of the receiver-related status flags (RDRF, IDLE, OR, NF, and FE) are
inhibited (cannot become set). Although RWU can be cleared by a software write to
SCCR2, to do so would be unusual. Normally RWU is set by software and is cleared
automatically with hardware. Whenever a new message begins, logic alerts the sleep-
ing receivers to wake up and evaluate the initial character of the new message.
Two methods of wakeup are available: idle-line wakeup and address-mark wakeup.
During idle-line wakeup, a sleeping receiver awakens as soon as the RxD line be-
comes idle. In the address-mark wakeup, logic one in the most significant bit (MSB) of
a character wakes up all sleeping receivers.
7.4.1 Idle-Line Wakeup
To use the receiver wakeup method, establish a software addressing scheme to allow
the transmitting devices to direct a message to individual receivers or to groups of re-
ceivers. This addressing scheme can take any form as long as all transmitting and re-
ceiving devices are programmed to understand the same scheme. Because the
addressing information is usually the first frame(s) in a message, receivers that are not
part of the current task do not become burdened with the entire set of addressing
frames. All receivers are awake (RWU = 0) when each message begins. As soon as
a receiver determines that the message is not intended for it, software sets the RWU
bit (RWU = 1), which inhibits further flag setting until the RxD line goes idle at the end
of the message. As soon as an idle line is detected by receiver logic, hardware auto-
matically clears the RWU bit so that the first frame of the next message can be re-
ceived. This type of receiver wakeup requires a minimum of one idle-line frame time
between messages, and no idle time between frames in a message.
7.4.2 Address-Mark Wakeup
The serial characters in this type of wakeup consist of seven (eight if M = 1) information
bits and an MSB, which indicates an address character (when set to one, or mark).
The first character of each message is an addressing character (MSB = 1). All receiv-
ers in the system evaluate this character to determine if the remainder of the message
is directed toward this particular receiver. As soon as a receiver determines that a
message is not intended for it, the receiver activates the RWU function by using a soft-
ware write to set the RWU bit. Because setting RWU inhibits receiver-related flags,
there is no further software overhead for the rest of this message.
When the next message begins, its first character has its MSB set, which automatically
clears the RWU bit and enables normal character reception. The first character whose
MSB is set is also the first character to be received after wakeup because RWU gets
cleared before the stop bit for that frame is serially received. This type of wakeup al-
lows messages to include gaps of idle time, unlike the idle-line method, but there is a
loss of efficiency because of the extra bit time for each character (address bit) required
for all characters.
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
SPC5515SAMLU66 MCU POWERPC 768K FLASH 176-LQFP
MCF5214CVM66 IC MPU 32BIT COLDF 256-MAPBGA
SPC5604PEF0MLQ6 IC MCU 32BIT 512KB FLASH 144LQFP
EGG.1B.308.CYM CONN RCPT 8POS PNL MNT SKT W/NUT
MC68HC16Z1CEH16 IC MCU 16BIT 16MHZ 132-PQFP
相关代理商/技术参数
参数描述
MCHC11KS1CFNE4 功能描述:8位微控制器 -MCU 68HC11KS4 RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
MCHC175AFR1 制造商:Rochester Electronics LLC 功能描述:- Bulk
MCHC40-330K-RC 制造商:ALLIED 制造商全称:Allied Components International 功能描述:Molded Chip Inductor High Current
MCHC705B16NCFNE 功能描述:IC MCU 8BIT 352 BYTES RAM 52PLCC RoHS:是 类别:集成电路 (IC) >> 嵌入式 - 微控制器, 系列:HC05 标准包装:1 系列:87C 核心处理器:MCS 51 芯体尺寸:8-位 速度:16MHz 连通性:SIO 外围设备:- 输入/输出数:32 程序存储器容量:8KB(8K x 8) 程序存储器类型:OTP EEPROM 大小:- RAM 容量:256 x 8 电压 - 电源 (Vcc/Vdd):4 V ~ 6 V 数据转换器:- 振荡器型:外部 工作温度:0°C ~ 70°C 封装/外壳:44-DIP 包装:管件 其它名称:864285
MCHC705B16NVFNE 功能描述:IC MCU 8BIT 15K OTP 52-PLCC RoHS:是 类别:集成电路 (IC) >> 嵌入式 - 微控制器, 系列:HC05 标准包装:1 系列:87C 核心处理器:MCS 51 芯体尺寸:8-位 速度:16MHz 连通性:SIO 外围设备:- 输入/输出数:32 程序存储器容量:8KB(8K x 8) 程序存储器类型:OTP EEPROM 大小:- RAM 容量:256 x 8 电压 - 电源 (Vcc/Vdd):4 V ~ 6 V 数据转换器:- 振荡器型:外部 工作温度:0°C ~ 70°C 封装/外壳:44-DIP 包装:管件 其它名称:864285