參數(shù)資料
型號: PIC16C745/JW
廠商: Microchip Technology
文件頁數(shù): 148/165頁
文件大?。?/td> 0K
描述: IC MCU EPROM8KX14 USB A/D 28CDIP
標準包裝: 15
系列: PIC® 16C
核心處理器: PIC
芯體尺寸: 8-位
速度: 24MHz
連通性: SCI,UART/USART,USB
外圍設備: 欠壓檢測/復位,POR,PWM,WDT
輸入/輸出數(shù): 22
程序存儲器容量: 14KB(8K x 14)
程序存儲器類型: EPROM,UV
RAM 容量: 256 x 8
電壓 - 電源 (Vcc/Vdd): 4.35 V ~ 5.25 V
數(shù)據(jù)轉換器: A/D 5x8b
振蕩器型: 外部
工作溫度: 0°C ~ 70°C
封裝/外殼: 28-CDIP(0.300",7.62mm)窗口
包裝: 管件
2000 Microchip Technology Inc.
Preliminary
DS41124C-page 83
PIC16C745/765
11.2.2
USART ASYNCHRONOUS RECEIVER
The receiver block diagram is shown in Figure 11-4.
The data is received on the RC7/RX/DT pin and drives
the data recovery block. The data recovery block is
actually a high speed shifter operating at x16 times the
baud rate, whereas the main receive serial shifter oper-
ates at the bit rate or at FINT.
Once Asynchronous mode is selected, reception is
enabled by setting bit CREN (RCSTA<4>).
The heart of the receiver is the receive (serial) shift reg-
ister (RSR). After sampling the STOP bit, the received
data in the RSR is transferred to the RCREG register (if
it is empty). If the transfer is complete, flag bit RCIF
(PIR1<5>) is set. The actual interrupt can be enabled/
disabled
by
setting/clearing
enable
bit
RCIE
(PIE1<5>). Flag bit RCIF is a read only bit which is
cleared by the hardware. It is cleared when the RCREG
register has been read and is empty. The RCREG is a
double buffered register, i.e., it is a two deep FIFO. It is
possible for two bytes of data to be received and trans-
ferred to the RCREG FIFO and a third byte to begin
shifting to the RSR register. On the detection of the
STOP bit of the third byte, if the RCREG register is still
full, then overrun error bit OERR (RCSTA<1>) will be
set. The word in the RSR will be lost. The RCREG reg-
ister can be read twice to retrieve the two bytes in the
FIFO. Overrun bit OERR has to be cleared in software.
This is done by resetting the receive logic (CREN is
cleared and then set). If bit OERR is set, transfers from
the RSR register to the RCREG register are inhibited,
so it is essential to clear error bit OERR if it is set. Fram-
ing error bit FERR (RCSTA<2>) is set if a stop bit is
detected as clear. Bit FERR and the 9th receive bit are
buffered the same way as the receive data. Reading
the RCREG, will load bits RX9D and FERR with new
values, therefore it is essential for the user to read the
RCSTA register before reading RCREG register in
order not to lose the old FERR and RX9D information.
FIGURE 11-4: USART RECEIVE BLOCK DIAGRAM
FIGURE 11-5: ASYNCHRONOUS RECEPTION
SPBRG
Baud Rate Generator
RC7/RX/DT
Pin Buffer
and Control
SPEN
Data
Recovery
CREN
OERR
FERR
RSR Register
MSb
LSb
RX9D
RCREG Register
FIFO
Interrupt
RCIF
RCIE
Data Bus
8
Stop
Start
(8)
7
1
0
RX9
Start
bit
bit7/8
bit1
bit0
bit7/8
bit0
Stop
bit
Start
bit
Start
bit
bit7/8
Stop
bit
RX (pin)
reg
Rcv buffer reg
Rcv shift
Read Rcv
buffer reg
RCREG
RCIF
(interrupt flag)
OERR bit
CREN
WORD 1
RCREG
WORD 2
RCREG
Stop
bit
Note: This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word,
causing the OERR (overrun) bit to be set.
745cov.book Page 83 Wednesday, August 2, 2000 8:24 AM
相關PDF資料
PDF描述
PIC16F723A-I/SS MCU PIC 7KB FLASH XLP 28-SSOP
PIC12C508A-04/SN IC MCU OTP 512X12 8SOIC
PIC12C509A-04/SM IC MCU OTP 1KX12 8-SOIJ
PIC16LF627T-04I/SO IC MCU FLASH 1KX14 COMP 18SOIC
PIC12C509A-04/P IC MCU OTP 1KX12 8DIP
相關代理商/技術參數(shù)
參數(shù)描述
PIC16C745T-I/SO 功能描述:8位微控制器 -MCU 14KB 256 RAM 22 I/O 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 最大時鐘頻率:50 MHz 程序存儲器大小: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 安裝風格:SMD/SMT
PIC16C74A/JW 功能描述:8位微控制器 -MCU 7KB 192 RAM 33 I/O 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 最大時鐘頻率:50 MHz 程序存儲器大小: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 安裝風格:SMD/SMT
PIC16C74A-04/L 功能描述:8位微控制器 -MCU 7KB 192 RAM 33 I/O 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 最大時鐘頻率:50 MHz 程序存儲器大小: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 安裝風格:SMD/SMT
PIC16C74A-04/L 制造商:Microchip Technology Inc 功能描述:8BIT CMOS MCU SMD 16C74 PLCC44
PIC16C74A-04/P 功能描述:8位微控制器 -MCU 7KB 192 RAM 33 I/O 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 最大時鐘頻率:50 MHz 程序存儲器大小: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 安裝風格:SMD/SMT