参数资料
| 型号： | AT89LP428-20AU |
| 厂商： | Atmel |
| 文件页数： | 125/149页 |
| 文件大小： | 0K |
| 描述： | MCU 8051 4K FLASH SPI 32TQFP |
| 产品培训模块： | MCU Product Line Introduction |
| 标准包装： | 250 |
| 系列： | 89LP |
| 核心处理器： | 8051 |
| 芯体尺寸： | 8-位 |
| 速度： | 20MHz |
| 连通性： | SPI，UART/USART |
| 外围设备： | 欠压检测/复位，POR，PWM，WDT |
| 输入/输出数： | 30 |
| 程序存储器容量： | 4KB（4K x 8） |
| 程序存储器类型： | 闪存 |
| EEPROM 大小： | 512 x 8 |
| RAM 容量： | 768 x 8 |
| 电压 - 电源 (Vcc/Vdd)： | 2.4 V ~ 5.5 V |
| 振荡器型： | 内部 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 32-TQFP |
| 包装： | 托盘 |
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77
3654A–MICRO–8/09
AT89LP428/828
16. Serial Interface (UART)
The serial interface on the AT89LP428/828 implements a Universal Asynchronous
Receiver/Transmitter (UART). The UART has the following features:
Full-duplex Operation
8 or 9 Data Bits
Framing Error Detection
Multiprocessor Communication Mode with Automatic Address Recognition
Baud Rate Generator Using Timer 1 or Timer 2
Interrupt on Receive Buffer Full or Transmission Complete
The serial interface is full-duplex, which means it can transmit and receive simultaneously. It is
also receive-buffered, which means it can begin receiving a second byte before a previously
received byte has been read from the receive register. (However, if the first byte still has not
been read when reception of the second byte is complete, one of the bytes will be lost.) The
serial port receive and transmit registers are both accessed at the Special Function Register
SBUF. Writing to SBUF loads the transmit register, and reading SBUF accesses a physically
separate receive register. The serial port can operate in the following four modes.
Mode 0: Serial data enters and exits through RXD. TXD outputs the shift clock. Eight data
bits are transmitted/received, with the LSB first. The baud rate is programmable to 1/2 or
1/4 the oscillator frequency, or variable based on Time 1.
Mode 1: 10 bits are transmitted (through TXD) or received (through RXD): a start bit (0),
8data bits (LSB first), and a stop bit (1). On receive, the stop bit goes into RB8 in the Special
Function Register SCON. The baud rate is variable based on Timer 1 or Timer 2.
Mode 2: 11 bits are transmitted (through TXD) or received (through RXD): a start bit (0),
8data bits (LSB first), a programmable 9th data bit, and a stop bit (1). On transmit, the 9th
data bit (TB8 in SCON) can be assigned the value of “0” or “1”. For example, the parity bit
(P, in the PSW) can be moved into TB8. On receive, the 9th data bit goes into RB8 in the
Special Function Register SCON, while the stop bit is ignored. The baud rate is
programmable to either 1/16 or 1/32 the oscillator frequency.
Mode 3: 11 bits are transmitted (through TXD) or received (through RXD): a start bit (0),
8data bits (LSB first), a programmable 9th data bit, and a stop bit (1). In fact, Mode 3 is the
same as Mode 2 in all respects except the baud rate, which is variable based on Timer 1 or
Timer 3 in Mode 3.
In all four modes, transmission is initiated by any instruction that uses SBUF as a destination
register. Reception is initiated in Mode 0 by the condition RI = 0 and REN = 1. Reception is initi-
ated in the other modes by the incoming start bit if REN = 1.
16.1
Multiprocessor Communications
Modes 2 and 3 have a special provision for multiprocessor communications. In these modes,
9data bits are received, followed by a stop bit. The 9th bit goes into RB8. Then comes a stop bit.
The port can be programmed such that when the stop bit is received, the serial port interrupt is
activated only if RB8 = 1. This feature is enabled by setting bit SM2 in SCON.
The following example shows how to use the serial interrupt for multiprocessor communications.
When the master processor must transmit a block of data to one of several slaves, it first sends
out an address byte that identifies the target slave. An address byte differs from a data byte in
that the 9th bit is “1” in an address byte and “0” in a data byte. With SM2 = 1, no slave is
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| AT89LP428-20JU | 功能描述:8位微控制器 -MCU SingleCycle 8051 4K ISP Flash 2.4V 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 |
| AT89LP428-20MH | 功能描述:8位微控制器 -MCU SingleCycle 8051 4K ISP Flash 2.4V 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 |
| AT89LP428-20PU | 功能描述:8位微控制器 -MCU SingleCycle 8051 4K ISP Flash 2.4V 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 |
| AT89LP51-20AU | 功能描述:8位微控制器 -MCU Single Cycle 8051 4K ISP FL 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 |
| AT89LP51-20JU | 功能描述:8位微控制器 -MCU Single Cycle 8051 4K ISP FL 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 |
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