The SPI operates in Ma" />
參數(shù)資料
型號: AT89C51ED2-SMSUM
廠商: Atmel
文件頁數(shù): 101/137頁
文件大?。?/td> 0K
描述: IC 8051 MCU FLASH 64K 68PLCC
產(chǎn)品培訓(xùn)模塊: MCU Product Line Introduction
標(biāo)準(zhǔn)包裝: 304
系列: 89C
核心處理器: 8051
芯體尺寸: 8-位
速度: 60MHz
連通性: SPI,UART/USART
外圍設(shè)備: POR,PWM,WDT
輸入/輸出數(shù): 50
程序存儲器容量: 64KB(64K x 8)
程序存儲器類型: 閃存
EEPROM 大?。?/td> 2K x 8
RAM 容量: 2K x 8
電壓 - 電源 (Vcc/Vdd): 2.7 V ~ 5.5 V
振蕩器型: 外部
工作溫度: -40°C ~ 85°C
封裝/外殼: 68-PLCC
包裝: 管件
配用: AT89OCD-01-ND - USB EMULATOR FOR AT8XC51 MCU
66
4235K–8051–05/08
AT89C51RD2/ED2
Figure 16-3. Full-Duplex Master-Slave Interconnection
16.3.1.1
Master Mode
The SPI operates in Master mode when the Master bit, MSTR (1), in the SPCON register is set.
Only one Master SPI device can initiate transmissions. Software begins the transmission from a
Master SPI Module by writing to the Serial Peripheral Data Register (SPDAT). If the shift register
is empty, the Byte is immediately transferred to the shift register. The Byte begins shifting out on
MOSI pin under the control of the serial clock, SCK. Simultaneously, another Byte shifts in from
the Slave on the Master’s MISO pin. The transmission ends when the Serial Peripheral transfer
data flag, SPIF, in SPSTA becomes set. At the same time that SPIF becomes set, the received
Byte from the Slave is transferred to the receive data register in SPDAT. Software clears SPIF
by reading the Serial Peripheral Status register (SPSTA) with the SPIF bit set, and then reading
the SPDAT.
16.3.1.2
Slave Mode
The SPI operates in Slave mode when the Master bit, MSTR (2), in the SPCON register is
cleared. Before a data transmission occurs, the Slave Select pin, SS, of the Slave device must
be set to ’0’. SS must remain low until the transmission is complete.
In a Slave SPI Module, data enters the shift register under the control of the SCK from the Mas-
ter SPI Module. After a Byte enters the shift register, it is immediately transferred to the receive
data register in SPDAT, and the SPIF bit is set. To prevent an overflow condition, Slave software
must then read the SPDAT before another Byte enters the shift register (3). A Slave SPI must
complete the write to the SPDAT (shift register) at least one bus cycle before the Master SPI
starts a transmission. If the write to the data register is late, the SPI transmits the data already in
the shift register from the previous transmission. The maximum SCK frequency allowed in slave
mode is F
CLK PERIPH /4.
16.3.2
Transmission Formats
Software can select any of four combinations of serial clock (SCK) phase and polarity using two
bits in the SPCON: the Clock Polarity (CPOL (4)) and the Clock Phase (CPHA4). CPOL defines
the default SCK line level in idle state. It has no significant effect on the transmission format.
CPHA defines the edges on which the input data are sampled and the edges on which the out-
put data are shifted (Figure 16-4 and Figure 16-5). The clock phase and polarity should be
identical for the Master SPI device and the communicating Slave device.
8-bit Shift register
SPI
Clock Generator
Master MCU
8-bit Shift register
MISO
MOSI
SCK
VSS
VDD
SS
Slave MCU
1.
The SPI Module should be configured as a Master before it is enabled (SPEN set). Also, the Mas-
ter SPI should be configured before the Slave SPI.
2.
The SPI Module should be configured as a Slave before it is enabled (SPEN set).
3.
The maximum frequency of the SCK for an SPI configured as a Slave is the bus clock speed.
4.
Before writing to the CPOL and CPHA bits, the SPI should be disabled (SPEN = ’0’).
相關(guān)PDF資料
PDF描述
AT89C51ED2-RDTUM IC 8051 MCU FLASH 64K 64VQFP
PX0852 COVER FOR USB FLASHDRIVE SEALED
VJ2225A271JBLAT4X CAP CER 270PF 630V 5% NP0 2225
AT32UC3C1128C-AUT IC MCU AVR32 128K FLASH 100TQFP
DF36012FPV IC H8 MCU FLASH 16K 64LQFP
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AT89C51ED2-UM 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:8-bit Flash Microcontroller
AT89C51IC2 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:8-bit Flash Microcontroller with 2-wire Interface
AT89C51IC2_04 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:8-bit Flash Microcontroller with 2-wire Interface
AT89C51IC2_08 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:8-bit Flash Microcontroller with 2-wire Interface
AT89C51IC2-RLRIL 功能描述:IC MCU FLASH 8051 32K 3V 44-VQFP RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器, 系列:89C 標(biāo)準(zhǔn)包裝:1 系列:AVR® ATmega 核心處理器:AVR 芯體尺寸:8-位 速度:16MHz 連通性:I²C,SPI,UART/USART 外圍設(shè)備:欠壓檢測/復(fù)位,POR,PWM,WDT 輸入/輸出數(shù):32 程序存儲器容量:32KB(16K x 16) 程序存儲器類型:閃存 EEPROM 大小:1K x 8 RAM 容量:2K x 8 電壓 - 電源 (Vcc/Vdd):2.7 V ~ 5.5 V 數(shù)據(jù)轉(zhuǎn)換器:A/D 8x10b 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 125°C 封裝/外殼:44-TQFP 包裝:剪切帶 (CT) 其它名稱:ATMEGA324P-B15AZCT