參數(shù)資料
型號(hào): VMX51C900
廠商: Electronic Theatre Controls, Inc.
英文描述: Versa Mix 8051 MCU with LCD Controller and ADC
中文描述: 8051反之亦然混合與LCD控制器和ADC的微控制器
文件頁數(shù): 22/55頁
文件大?。?/td> 2395K
代理商: VMX51C900
VMX51C900
______________________________________________________________________________________________
www.ramtron.com
page 22 of 55
UART Operation in Mode 1
In Mode 1 operation, 10 bits are transmitted (through
TXD) or received (through RXD). The transactions are
composed of: a Start bit (Low); 8 data bits (LSB first)
and one Stop bit (high). The reception is completed
once the Stop bit sets the RB8 flag in the SCON
register. Either Timer 1 or Timer 2 controls the baud
rate in this mode.
The following diagram shows the serial port structure
when configured in Mode 1.
F
IGURE
13:
S
ERIAL
P
ORT
M
ODE
1
AND
3
B
LOCK
D
IAGRAM
Internal Bus
SBUF
D
S
Q
ZERO DETECTOR
CLK
1
Write to
SBUF
TX Control Unit
Start
TX Clock
Data
Send
RX Control Unit
RI
TI
RX Clock
Start
SHIFT
9-Bit Shift Register
SBUF
Internal Bus
READ SBUF
LOAD SBUF
Serial Port
Interrupt
Shift
Bit
Detector
÷16
÷16
1-0 Transition
Detector
RXD
÷2
Timer 2
Overflow
Timer 1
Overflow
RCLK
TCLK
SMOD
0
1
0
1
0
1
Load
SBUF
Shift
TXD
UART Transmission in Mode 1
Transmission in this mode is initiated by any
instruction that makes use of SBUF as a destination
register. The 9
th
bit position of the transmit shift register
is loaded by the “write to SBUF” signal. This event also
flags/informs the TX Control Unit that a transmission
has been requested.
It is after the next rollover in the divide-by-16 counter
when transmission actually begins. It follows that the
bit times are synchronized to the divide-by-16 counter
and not to the “write to SBUF” signal.
When a transmission begins, it places the start bit at
TXD. Data transmission is activated one bit time later.
This activation enables the output bit of the transmit
shift register to TXD. One bit time after that, the first
shift pulse occurs.
In this Mode, zeros are clocked in from the left as data
bits are shifted out to the right. When the most
significant bit of the data byte is at the output position
of the shift register, the 1 that was initially loaded into
the 9
th
position is to the immediate left of the MSB, and
all positions to the left of that contain zeros. This
condition flags the TX Control Unit to shift one more
time.
UART Reception in Mode 1
A one to zero transition at pin RXD will initiate
reception. It is for this reason that RXD is sampled at a
rate of 16 multiplied by the baud rate that has been
established. When a transition is detected, 1FFh is
written into the input shift register and the divide-by-16
counter is immediately reset. The divide-by-16 counter
is reset in order to align its rollovers with the
boundaries of the incoming bit times.
In total, there are 16 states in the counter. During the
7
th
, 8
th
and 9
th
counter states of each bit time; the bit
detector samples the value of RXD. The accepted
value is the value that was seen in at least two of the
three samples. The purpose of doing this is for noise
rejection. If the value accepted during the first bit time
is not zero, the receive circuits are reset and the unit
goes back to searching for another one to zero
transition. All false start bits are rejected by doing this.
If the start bit is valid, it is shifted into the input shift
register, and the reception of the rest of the frame will
proceed.
For a receive operation, the data bits come in from the
right as 1’s shift out on the left. As soon as the start bit
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
VMX51C900-25-L 功能描述:8位微控制器 -MCU 8K+256 25MHz 5V 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
VMX51C900-25-LG 功能描述:8位微控制器 -MCU 8K+256 25MHz 5V 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
VMX51C900-25-L-G 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Versa Mix 8051 MCU with LCD Controller and ADC
VMX51C900-25-P 功能描述:8位微控制器 -MCU 8K+256 25MHz 5V 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
VMX51C900-25-PG 功能描述:8位微控制器 -MCU 8K+256 25MHz 5V 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