參數(shù)資料
型號: HPC26004
廠商: National Semiconductor Corporation
英文描述: High-Performance microController
中文描述: 高性能微控制器
文件頁數(shù): 23/37頁
文件大?。?/td> 487K
代理商: HPC26004
HPC46064 UART
The HPC46064 contains a software programmable UART.
The UART (seeFigure 26 ) consists of a transmit shift regis-
ter, a receiver shift register and five addressable registers,
as follows: a transmit buffer register (TBUF), a receiver buff-
er register (RBUF), a UART control and status register
(ENU), a UART receive control and status register (ENUR)
and a UART interrupt and clock source register (ENUI). The
ENU register contains flags for transmit and receive func-
tions; this register also determines the length of the data
frame (8 or 9 bits) and the value of the ninth bit in transmis-
sion. The ENUR register flags framing and data overrun er-
rors while the UART is receiving. Other functions of the
ENUR register include saving the ninth bit received in the
data frame and enabling or disabling the UART’s Wake-up
Mode of operation. The determination of an internal or ex-
ternal clock source is done by the ENUI register, as well as
selecting the number of stop bits and enabling or disabling
transmit and receive interrupts.
The baud rate clock for the Receiver and Transmitter can
be selected for either an internal or external source using
two bits in the ENUI register. The internal baud rate is pro-
grammed by the DIVBY register. The baud rate may be se-
lected from a range of 8 Hz to 128 kHz in binary steps or T3
underflow. By selecting a 9.83 MHz crystal, all standard
baud rates from 75 baud to 38.4 kBaud can be generated.
The external baud clock source comes from the CKX pin.
The Transmitter and Receiver can be run at different rates
by selecting one to operate from the internal clock and the
other from an external source.
The HPC46064 UART supports two data formats. The first
format for data transmission consists of one start bit, eight
data bits and one or two stop bits. The second data format
for transmission consists of one start bit, nine data bits, and
one or two stop bits. Receiving formats differ from transmis-
sion only in that the Receiver always requires only one stop
bit in a data frame.
UART Wake-up Mode
The HPC46064 UART features a Wake-up Mode of opera-
tion. This mode of operation enables the HPC46064 to be
networked with other processors. Typically in such environ-
ments, the messages consist of addresses and actual data.
Addresses are specified by having the ninth bit in the data
frame set to 1. Data in the message is specified by having
the ninth bit in the data frame reset to 0.
The UART monitors the communication stream looking for
addresses. When the data word with the ninth bit set is
received, the UART signals the HPC46064 with an interrupt.
The processor then examines the content of the receiver
buffer to decide whether it has been addressed and whether
to accept subsequent data.
TL/DD/11372–24
FIGURE 26. UART Block Diagram
23
相關PDF資料
PDF描述
HPC26064 High-Performance microController
HPC36004 High-Performance microController
HPC36064 High-Performance microController
HPC46064 High-Performance microController
HPC3130PBK PCI Bus Interface/Controller
相關代理商/技術參數(shù)
參數(shù)描述
HPC26004E20 制造商:未知廠家 制造商全稱:未知廠家 功能描述:16-Bit Microcontroller
HPC26004E30 制造商:未知廠家 制造商全稱:未知廠家 功能描述:16-Bit Microcontroller
HPC26004EL20 制造商:未知廠家 制造商全稱:未知廠家 功能描述:16-Bit Microcontroller
HPC26004EL30 制造商:未知廠家 制造商全稱:未知廠家 功能描述:16-Bit Microcontroller
HPC26004L20 制造商:未知廠家 制造商全稱:未知廠家 功能描述:16-Bit Microcontroller