參數(shù)資料
型號: M30612E4
廠商: Mitsubishi Electric Corporation
英文描述: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
中文描述: 單片16位CMOS微機
文件頁數(shù): 68/197頁
文件大?。?/td> 2673K
代理商: M30612E4
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁當前第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁第77頁第78頁第79頁第80頁第81頁第82頁第83頁第84頁第85頁第86頁第87頁第88頁第89頁第90頁第91頁第92頁第93頁第94頁第95頁第96頁第97頁第98頁第99頁第100頁第101頁第102頁第103頁第104頁第105頁第106頁第107頁第108頁第109頁第110頁第111頁第112頁第113頁第114頁第115頁第116頁第117頁第118頁第119頁第120頁第121頁第122頁第123頁第124頁第125頁第126頁第127頁第128頁第129頁第130頁第131頁第132頁第133頁第134頁第135頁第136頁第137頁第138頁第139頁第140頁第141頁第142頁第143頁第144頁第145頁第146頁第147頁第148頁第149頁第150頁第151頁第152頁第153頁第154頁第155頁第156頁第157頁第158頁第159頁第160頁第161頁第162頁第163頁第164頁第165頁第166頁第167頁第168頁第169頁第170頁第171頁第172頁第173頁第174頁第175頁第176頁第177頁第178頁第179頁第180頁第181頁第182頁第183頁第184頁第185頁第186頁第187頁第188頁第189頁第190頁第191頁第192頁第193頁第194頁第195頁第196頁第197頁
Mitsubishi microcomputers
M16C / 61 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
DMAC
68
DMA enable bit
Setting the DMA enable bit to 1 makes the DMAC active. The DMAC carries out the following operations at
the time data transfer starts immediately after DMAC is turned active.
(1) Reloads the value of one of the source pointer and the destination pointer - the one specified for the
forward direction - to the forward direction address pointer.
(2) Reloads the value of the transfer counter reload register to the transfer counter.
Thus overwriting 1 to the DMA enable bit with the DMAC being active carries out the operations given
above, so the DMAC operates again from the initial state at the instant 1 is overwritten to the DMA enable
bit.
DMA request bit
The DMAC can generate a DMA transfer request signal triggered by a factor chosen in advance out of DMA
request factors for each channel.
DMA request factors include the following.
* Factors effected by using the interrupt request signals from the built-in peripheral functions and software
DMA factors (internal factors) effected by a program.
* External factors effected by utilizing the input from external interrupt signals.
For the selection of DMA request factors, see the descriptions of the DMAi factor selection register.
The DMA request bit turns to 1 if the DMA transfer request signal occurs regardless of the DMAC's state
(regardless of whether the DMA enable bit is set 1 or to 0). It turns to 0 immediately before data transfer
starts.
In addition, it can be set to 0 by use of a program, but cannot be set to 1.
There can be instances in which a change in DMA request factor selection bit causes the DMA request bit
to turn to 1. So be sure to set the DMA request bit to 0 after the DMA request factor selection bit is changed.
The DMA request bit turns to 1 if a DMA transfer request signal occurs, and turns to 0 immediately before
data transfer starts. If the DMAC is active, data transfer starts immediately, so the value of the DMA request
bit, if read by use of a program, turns out to be 0 in most cases. To examine whether the DMAC is active,
read the DMA enable bit.
Here follows the timing of changes in the DMA request bit.
(1) Internal factors
Except the DMA request factors triggered by software, the timing for the DMA request bit to turn to 1 due
to an internal factor is the same as the timing for the interrupt request bit of the interrupt control register to
turn to 1 due to several factors.
Turning the DMA request bit to 1 due to an internal factor is timed to be effected immediately before the
transfer starts.
(2) External factors
An external factor is a factor caused to occur by the leading edge of input from the INTi pin (i depends on
which DMAC channel is used).
Selecting the INTi pins as external factors using the DMA request factor selection bit causes input from
these pins to become the DMA transfer request signals.
The timing for the DMA request bit to turn to 1 when an external factor is selected synchronizes with the
signal's edge applicable to the function specified by the DMA request factor selection bit (synchronizes
with the trailing edge of the input signal to each INTi pin, for example).
With an external factor selected, the DMA request bit is timed to turn to 0 immediately before data transfer
starts similarly to the state in which an internal factor is selected.
相關(guān)PDF資料
PDF描述
M30612M4-152FP SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
M30612M4A SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
M30612M4A-417GP SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
M30612M4A-422GP SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
M30612M8A SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
M30612E4FP 制造商:MITSUBISHI 制造商全稱:Mitsubishi Electric Semiconductor 功能描述:SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
M30612E4GP 制造商:MITSUBISHI 制造商全稱:Mitsubishi Electric Semiconductor 功能描述:SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
M30612M4-152FP 制造商:MITSUBISHI 制造商全稱:Mitsubishi Electric Semiconductor 功能描述:SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
M30612M4-155FP 制造商:MITSUBISHI 制造商全稱:Mitsubishi Electric Semiconductor 功能描述:SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
M30612M4A 制造商:MITSUBISHI 制造商全稱:Mitsubishi Electric Semiconductor 功能描述:SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER