參數(shù)資料
型號(hào): AT89LP52-20JU
廠商: Atmel
文件頁(yè)數(shù): 83/117頁(yè)
文件大?。?/td> 0K
描述: IC MCU 8051 8K FLASH SPI 44PLCC
標(biāo)準(zhǔn)包裝: 27
系列: 89LP
核心處理器: 8051
芯體尺寸: 8-位
速度: 20MHz
連通性: EBI/EMI,I²C,SPI,UART/USART
外圍設(shè)備: 欠壓檢測(cè)/復(fù)位,POR,PWM,WDT
輸入/輸出數(shù): 36
程序存儲(chǔ)器容量: 8KB(8K x 8)
程序存儲(chǔ)器類型: 閃存
RAM 容量: 256 x 8
電壓 - 電源 (Vcc/Vdd): 2.4 V ~ 5.5 V
振蕩器型: 內(nèi)部
工作溫度: -40°C ~ 85°C
封裝/外殼: 44-LCC(J 形引線)
包裝: *
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)第17頁(yè)第18頁(yè)第19頁(yè)第20頁(yè)第21頁(yè)第22頁(yè)第23頁(yè)第24頁(yè)第25頁(yè)第26頁(yè)第27頁(yè)第28頁(yè)第29頁(yè)第30頁(yè)第31頁(yè)第32頁(yè)第33頁(yè)第34頁(yè)第35頁(yè)第36頁(yè)第37頁(yè)第38頁(yè)第39頁(yè)第40頁(yè)第41頁(yè)第42頁(yè)第43頁(yè)第44頁(yè)第45頁(yè)第46頁(yè)第47頁(yè)第48頁(yè)第49頁(yè)第50頁(yè)第51頁(yè)第52頁(yè)第53頁(yè)第54頁(yè)第55頁(yè)第56頁(yè)第57頁(yè)第58頁(yè)第59頁(yè)第60頁(yè)第61頁(yè)第62頁(yè)第63頁(yè)第64頁(yè)第65頁(yè)第66頁(yè)第67頁(yè)第68頁(yè)第69頁(yè)第70頁(yè)第71頁(yè)第72頁(yè)第73頁(yè)第74頁(yè)第75頁(yè)第76頁(yè)第77頁(yè)第78頁(yè)第79頁(yè)第80頁(yè)第81頁(yè)第82頁(yè)當(dāng)前第83頁(yè)第84頁(yè)第85頁(yè)第86頁(yè)第87頁(yè)第88頁(yè)第89頁(yè)第90頁(yè)第91頁(yè)第92頁(yè)第93頁(yè)第94頁(yè)第95頁(yè)第96頁(yè)第97頁(yè)第98頁(yè)第99頁(yè)第100頁(yè)第101頁(yè)第102頁(yè)第103頁(yè)第104頁(yè)第105頁(yè)第106頁(yè)第107頁(yè)第108頁(yè)第109頁(yè)第110頁(yè)第111頁(yè)第112頁(yè)第113頁(yè)第114頁(yè)第115頁(yè)第116頁(yè)第117頁(yè)
68
3709D–MICRO–12/11
AT89LP51/52
14.6
More About Mode 1
Ten bits are transmitted (through TXD), or received (through RXD): a start bit (0), 8 data bits
(LSB first), and a stop bit (1). On receive, the stop bit goes into RB8 in SCON. In the
AT89LP51/52, the baud rate is determined either by the Timer 1 overflow rate, the TImer 2 over-
flow rate, or both. In this case one timer is for transmit and the other is for receive. Figure 14-6
shows a simplified functional diagram of the serial port in Mode 1 and associated timings for
transmit and receive.
Transmission is initiated by any instruction that uses SBUF as a destination register. The “write
to SBUF” signal also loads a “1” into the 9th bit position of the transmit shift register and flags the
TX Control unit that a transmission is requested. Transmission actually commences at S1P1 of
the machine cycle following the next rollover in the divide-by-16 counter. Thus, the bit times are
synchronized to the divide-by-16 counter, not to the “write to SBUF” signal.
The transmission begins when SEND is activated, which puts the start bit at TXD. One bit time
later, DATA is activated, which enables the output bit of the transmit shift register to TXD. The
first shift pulse occurs one bit time after that.
As data bits shift out to the right, “0”s are clocked in from the left. When the MSB of the data byte
is at the output position of the shift register, the “1” that was initially loaded into the 9th position is
just to the left of the MSB, and all positions to the left of that contain “0”s. This condition flags the
TX Control unit to do one last shift, then deactivate SEND and set TI. This occurs at the tenth
divide-by-16 rollover after “write to SBUF.”
Reception is initiated by a 1-to-0 transition detected at RXD. For this purpose, RXD is sampled
at a rate of 16 times the established baud rate. When a transition is detected, the divide-by-16
counter is immediately reset, and 1FFH is written into the input shift register. Resetting the
divide-by-16 counter aligns its roll-overs with the boundaries of the incoming bit times.
The 16 states of the counter divide each bit time into 16ths. At the 7th, 8th, and 9th counter
states of each bit time, the bit detector samples the value of RXD. The value accepted is the
value that was seen in at least 2 of the 3 samples. This is done to reject noise. In order to reject
false bits, if the value accepted during the first bit time is not 0, the receive circuits are reset and
the unit continues looking for another 1-to-0 transition. If the start bit is valid, it is shifted into the
input shift register, and reception of the rest of the frame proceeds.
As data bits come in from the right, “1”s shift out to the left. When the start bit arrives at the left-
most position in the shift register, (which is a 9-bit register in Mode 1), it flags the RX Control
block to do one last shift, load SBUF and RB8, and set RI. The signal to load SBUF and RB8
and to set RI is generated if, and only if, the following conditions are met at the time the final shift
pulse is generated.
RI = 0 and
Either SM2 = 0, or the received stop bit = 1
If either of these two conditions is not met, the received frame is irretrievably lost. If both condi-
tions are met, the stop bit goes into RB8, the 8 data bits go into SBUF, and RI is activated. At
this time, whether or not the above conditions are met, the unit continues looking for a 1-to-0
transition in RXD.
相關(guān)PDF資料
PDF描述
AT89S4051-24PU MCU 8051 4K FLASH 24MHZ 20-PDIP
AT89LP2052-20SU IC 8051 MCU FLASH 2K 20SOIC
AT89LP52-20AU IC MCU 8051 8K FLASH SPI 44TQFP
AT89LP52-20PU IC MCU 8051 8K FLASH SPI 40PDIP
ATMEGA48PA-MMN MCU AVR 4KB FLASH 20MHZ 28QFN
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AT89LP52-20MU 功能描述:8位微控制器 -MCU Single-Cycle 8051 8K ISP Flash MCU RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
AT89LP52-20PU 功能描述:8位微控制器 -MCU Single-Cycle 8051 8K ISP Flash MCU RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
AT89LP6440-20AU 功能描述:8位微控制器 -MCU Single-Cycle 8051 64K ISP Flash RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
AT89LP6440-20JU 功能描述:8位微控制器 -MCU Single-Cycle 8051 64K ISP Flash RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
AT89LP6440-20MU 功能描述:8位微控制器 -MCU Single-Cycle 8051 64K ISP Flash RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT