参数资料
型号: MC68HC11G5CFN
厂商: MOTOROLA INC
元件分类: 微控制器/微处理器
英文描述: High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcontroller
中文描述: 8-BIT, MROM, 2.1 MHz, MICROCONTROLLER, PQCC84
封装: PLASTIC, LCC-84
文件页数: 123/195页
文件大小: 839K
代理商: MC68HC11G5CFN
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页第82页第83页第84页第85页第86页第87页第88页第89页第90页第91页第92页第93页第94页第95页第96页第97页第98页第99页第100页第101页第102页第103页第104页第105页第106页第107页第108页第109页第110页第111页第112页第113页第114页第115页第116页第117页第118页第119页第120页第121页第122页当前第123页第124页第125页第126页第127页第128页第129页第130页第131页第132页第133页第134页第135页第136页第137页第138页第139页第140页第141页第142页第143页第144页第145页第146页第147页第148页第149页第150页第151页第152页第153页第154页第155页第156页第157页第158页第159页第160页第161页第162页第163页第164页第165页第166页第167页第168页第169页第170页第171页第172页第173页第174页第175页第176页第177页第178页第179页第180页第181页第182页第183页第184页第185页第186页第187页第188页第189页第190页第191页第192页第193页第194页第195页
MC68HC11G5
PULSE WIDTH MODULATION TIMER
MOTOROLA
10-3
10.2
CLOCK SELECTION
There are three available clocks (A, B and S). Clock A can be software-selected to be E, E/
2, E/4 or E/8. Clock B can be software selected to be E, E/2, E/4,..., E/128. The block diagram
of Figure 10-1 depicts the three different clocks and how the scaled clock is created.
The scaled clock (S) uses clock A as an input and divides it with a reloadable counter. This counter
is compared with a user programmable scale value (in the PWSCAL register). When they match,
a pulse is output and the 8-bit counter is reset. The output signal from this circuit is then divided by
two to give clock S. The rates available for clock S, therefore, are software selectable to be clock A
divided by 2 down to clock A divided by 512 in increments of 2.
Each PWM timer channel can be driven by one of two clocks, selected in software: Channels 1 and 2
can use clock A or clock S; Channels 3 and 4 can use clock B or clock S.
Writing to PWSCAL causes the 8-bit counter to be reset to $00. Otherwise, when changing from a
low rate to a higher rate, it would be possible for the counter to miss the new value and have to go
all the way to $FF and wrap back around before counting at the proper rate. Forcing the counter to
$00 every time it is written prevents this.
10.3
16-BIT PWM FUNCTION
The PWCLK register contains two control bits, each of which is used to concatenate a pair of PWM
channels into one 16-bit channel. Concatenation of channels 3 and 4 is controlled by the CON34
bit; similarly, channels 1 and 2 are concatenated using the CON12 bit.
When channels 3 and 4 are concatenated, channel 3 registers become the high order bytes of the
double byte channel. Reading the counter high order byte causes the low order byte to be latched
for one cycle, to guarantee that double byte reads will be accurate. Writing to the low byte of the
counter (channel 4) causes the entire counter to be reset. Writing to the upper byte of the counter
has no effect.
Similarly, when channels 1 and 2 are concatenated, channel 1 registers become the high order bytes
of the double byte channel.
The 16-bit duty register and period register are obtained by concatenating the two 8-bit duty registers
and period registers, respectively. Writing to these registers takes twice as many write cycles as for
the 8-bit PWM. The 16-bit PWM circuit has secondary buffers internally, and the user should write
to these 16-bit registers using 16-bit write instructions or high byte to low byte sequential write
instructions. During the two-byte write sequence, the secondary buffer will not be loaded from the
16-bit register. The 16-bit duty and period registers can be written to at any time; the written value
will take effect from the next cycle of the PWM period.
相关PDF资料
PDF描述
MC68HLC908LJ12 Addendum to MC68HC908LJ12
MC68HLC908QT1 Microcontrollers
MC68HLC908QT2 Microcontrollers
MC68HLC908QT4 Microcontrollers
MC68HLC908QY1 Microcontrollers
相关代理商/技术参数
参数描述
MC68HC11G7 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
MC68HC11G7CFN 制造商:未知厂家 制造商全称:未知厂家 功能描述:8-Bit Microcontroller
MC68HC11K0 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:HCMOS Microcontroller Unit
MC68HC11K0CFN2 制造商:MOTOROLA 制造商全称:Motorola, Inc 功能描述:8-Bit Microcontroller
MC68HC11K0CFN3 制造商:MOTOROLA 制造商全称:Motorola, Inc 功能描述:8-Bit Microcontroller