欧美成人免费电影,国产欧美一区二区三区精品酒店,精品国产a毛片,色网在线免费观看

參數資料
型號: MC68B912B32
廠商: Motorola, Inc.
英文描述: 2.5V 100ppm/Degrees C, 50uA in SOT23-3 Series (Bandgap) Voltage Reference 3-SOT-23 -40 to 125
中文描述: 16位微控制器
文件頁數: 32/128頁
文件大小: 748K
代理商: MC68B912B32
MOTOROLA
32
MC68HC912B32
MC68HC912B32TS/D
6 Bus Control and Input/Output
Internally the MC68HC912B32 has full 16-bit data paths, but depending upon the operating mode and
control registers, the external bus may be eight or sixteen bits. There are cases where 8-bit and 16-bit
accesses can appear on adjacent cycles using the LSTRB signal to indicate 8- or 16-bit data.
6.1 Detecting Access Type from External Signals
The external signals LSTRB, R/W, and A0 can be used to determine the type of bus access that is tak-
ing place. Accesses to the internal RAM module are the only type of access that produce LSTRB=A0=1,
because the internal RAM is specifically designed to allow misaligned 16-bit accesses in a single cycle.
In these cases the data for the address that was accessed is on the low half of the data bus and the
data for address + 1 is on the high half of the data bus (data order is swapped).
6.2 Registers
Not all registers are visible in the MC68HC912B32 memory map under certain conditions. In special
peripheral mode the first 16 registers associated with bus expansion are removed from the memory
map.
In expanded modes, some or all of port A, port B, and port E are used for expansion buses and control
signals. In order to allow emulation of the single-chip functions of these ports, some of these registers
must be rebuilt in an external port replacement unit. In any expanded mode port A and port B are used
for address and data lines so registers for these ports, as well as the data direction registers for these
ports, are removed from the on-chip memory map and become external accesses.
In any expanded mode, port E pins may be needed for bus control (e.g., ECLK, R/W). To regain the
single-chip functions of port E, the emulate port E (EME) control bit in the MODE register may be set.
In this special case of expanded mode and EME set, PORTE and DDRE registers are removed from
the on-chip memory map and become external accesses so port E may be rebuilt externally.
Table 13 Access Type vs. Bus Control Pins
LSTRB
1
0
1
0
0
A0
0
1
0
1
0
R/W
1
1
0
0
1
Type of Access
8-bit read of an even address
8-bit read of an odd address
8-bit write to an even address
8-bit write to an odd address
16-bit read of an even address
16-bit read of an odd address
(low/high data swapped)
16-bit write to an even address
16-bit write to an even address
(low/high data swapped)
1
1
1
0
0
0
1
1
0
相關PDF資料
PDF描述
MC68C912B32FU8 16-Bit Microcontroller
MC68B912B32FU8 16-Bit Microcontroller
MC68C912B32CFU8 16-Bit Microcontroller
MC68CK338 Highly Integrated, Low-Power, 32-Bit Microcontroller
MC68EC060 32-Bit Microprocessors.(32位微處理器)
相關代理商/技術參數
參數描述
MC68B912B32FU8 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:16-Bit Microcontroller
MC68BOOL 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:8-BIT MICROPROCESSING UNIT (MPU)
MC68BOOP 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:8-BIT MICROPROCESSING UNIT (MPU)
MC68BOOS 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:8-BIT MICROPROCESSING UNIT (MPU)
MC68C812A4 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:Technical Supplement MC68C812A4 3.3V Electrical Characteristics
主站蜘蛛池模板: 怀远县| 内黄县| 石泉县| 尉氏县| 沛县| 贵阳市| 博白县| 庄浪县| 安阳县| 馆陶县| 饶平县| 翁源县| 广汉市| 河曲县| 嘉峪关市| 筠连县| 武夷山市| 罗城| 寿宁县| 饶河县| 西平县| 南岸区| 渑池县| 金溪县| 石城县| 宿迁市| 新野县| 巴中市| 遂昌县| 雷波县| 莱州市| 五指山市| 邻水| 黄冈市| 炎陵县| 牙克石市| 潮安县| 宁安市| 偃师市| 阳原县| 邯郸市|