- 您现在的位置：买卖IC网 > PDF目录10917 > DS80C310-QNG+T&R (Maxim Integrated Products)IC MCU HI SPEED 25MHZ IND 44PLCC PDF资料下载
参数资料
| 型号： | DS80C310-QNG+T&R |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 21/22页 |
| 文件大小： | 0K |
| 描述： | IC MCU HI SPEED 25MHZ IND 44PLCC |
| 标准包装： | 500 |
| 系列： | 80C |
| 核心处理器： | 8051 |
| 芯体尺寸： | 8-位 |
| 速度： | 25MHz |
| 连通性： | EBI/EMI，SIO，UART/USART |
| 外围设备： | 欠压检测/复位，POR |
| 输入/输出数： | 32 |
| 程序存储器类型： | ROMless |
| RAM 容量： | 256 x 8 |
| 电压 - 电源 (Vcc/Vdd)： | 4.5 V ~ 5.5 V |
| 振荡器型： | 外部 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 44-LCC（J 形引线） |
| 包装： | 带卷 (TR) |
DS80C310
8 of 22
MEMORY ACCESS
The DS80C310 has 256 bytes of scratchpad RAM, but contains no on-chip ROM. Off-chip memory is
accessed using the multiplexed address/data bus on P0 and the MSB address on P2. Timing diagrams are
provided in the Absolute Maximum Ratings section. Program memory (ROM) is accessed at a fixed rate
determined by the crystal frequency and the actual instructions. As mentioned above, an instruction cycle
requires 4 clocks. Data memory (RAM) is accessed according to a variable speed MOVX instruction as
described below.
STRETCH MEMORY CYCLE
The DS80C310 allows the application software to adjust the speed of data memory access. The
microcontroller can perform the MOVX in as few as 2 instruction cycles. However, this value can be
stretched as needed so that both fast memory and slow memory or peripherals can be accessed with no
glue logic. Even in high-speed systems, it may not be necessary or desirable to perform data memory
access at full speed. In addition, there are a variety of memory-mapped peripherals such as LCD displays
or UARTs that are not fast.
The stretch MOVX is controlled by the Clock Control Register at SFR location 8Eh as described below.
This allows the user to select a stretch value between 0 and 7. A stretch of 0 results in a 2-machine-cycle
MOVX. A stretch of 7 results in a MOVX of 9 machine cycles. Software can dynamically change this
value depending on the particular memory or peripheral.
On reset, the stretch value defaults to 1, resulting in a 3-cycle MOVX. Therefore, RAM access is not
performed at full speed. This is a convenience to existing designs that may not have fast RAM in place.
When maximum speed is desired, the software should select a stretch value of 0. When using very slow
RAM or peripherals, a larger stretch value can be selected. Note that this affects data memory only and
the only way to slow program memory (ROM) access is to use a slower crystal.
Using a stretch value between 1 and 7 causes the microcontroller to stretch the read/write strobe and all
related timing. This results in a wider read/write strobe allowing more time for memory/peripherals to
respond. The timing of the variable speed MOVX is shown in the Absolute Maximum Ratings section.
Note that full speed access is not the reset default case. Table 2 shows the resulting strobe widths for each
stretch value. The memory stretch is implemented using the Clock Control Special Function Register at
SFR location 8Eh. The stretch value is selected using bits CKCON.2–CKCON.0. In the table, these bits
are referred to as M2 through M0. The first stretch (default) allows the use of common 120ns or 150ns
RAMs without dramatically lengthening the memory access.
相关PDF资料 |
PDF描述 |
|---|---|
| VE-23M-IX-F4 | CONVERTER MOD DC/DC 10V 75W |
| VE-23M-IX-F3 | CONVERTER MOD DC/DC 10V 75W |
| VE-23M-IX-F2 | CONVERTER MOD DC/DC 10V 75W |
| VE-J3H-IY-B1 | CONVERTER MOD DC/DC 52V 50W |
| VE-J3F-IY-B1 | CONVERTER MOD DC/DC 72V 50W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS80C320 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:High-Speed/Low-Power Microcontrollers |
| DS80C320_06 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:High-Speed/Low-Power Microcontrollers |
| DS80C320+ENL | 制造商:Maxim Integrated Products 功能描述:MCU 8BIT CISC ROMLESS 5V 44TQFP - Trays |
| DS80C320+FCG | 制造商:Maxim Integrated Products 功能描述:MICRO HI SPD 44PQFP 25MHZ PB-FREE - Trays |
| DS80C320+FNG | 制造商:Maxim Integrated Products 功能描述:MICRO HS 44MQFP 25MHZ IND PB-FREE - Trays |
发布紧急采购，3分钟左右您将得到回复。