單片機(jī)作為一種微型計(jì)算機(jī)，其內(nèi)部具有一定的存儲(chǔ)單元（8031除外），但由于其內(nèi)部存儲(chǔ)單元及端口有限，很多情況下難以滿足實(shí)際需求。為此介紹一種新的擴(kuò)展方法，將數(shù)據(jù)線與地址線合并使用，通過(guò)軟件控制的方法實(shí)現(xiàn)數(shù)據(jù)線與地址線功能的分時(shí)轉(zhuǎn)換，數(shù)據(jù)線不僅用于傳送數(shù)據(jù)信號(hào)，還可作為地址線、控制線，用于傳送地址信號(hào)和控制信號(hào)，從而實(shí)現(xiàn)單片機(jī)與存儲(chǔ)器件的有效連接。以單片機(jī)片外256KB數(shù)據(jù)存儲(chǔ)空間的擴(kuò)展為例，通過(guò)該擴(kuò)展方法，僅用10個(gè)I/O端口便可實(shí)現(xiàn)，與傳統(tǒng)的擴(kuò)展方法相比，可節(jié)約8個(gè)I/O端口。
Abstract:
As a micro-computer,the SCM internal memory has a certain units(except8031),but because of its internal storage units and the ports are limited,in many cases it can not meet the actual demand.So we introduced a new extension method,the data line and address lines combined through software-controlled approach to realize the time-conversion functions of data lines and address lines,so the data lines not only transmited data signals,but also served as address lines and control lines to transmit address signals and control signals,in order to achieve an effective connection of microcontroller and memory chips.Take microcontroller chip with256KB of data storage space expansion as example,through this extension method,with only10I/O ports it was achieved,compared with the traditional extension methods,this method saves8I/O ports.
MMC/SD卡以其優(yōu)越的性能，在單片機(jī)嵌入式設(shè)備中得到廣泛應(yīng)用。將MMC/SD卡作為外部掉電存儲(chǔ)介質(zhì)應(yīng)用于音頻信號(hào)發(fā)生器中，通過(guò)8051F330單片機(jī)上的SPI接口，實(shí)現(xiàn)單片機(jī)—MMC/SD卡的存儲(chǔ)擴(kuò)展，設(shè)計(jì)了此硬件平臺(tái)上的MMC/SD卡的單片機(jī)驅(qū)動(dòng)程序，并給出了相應(yīng)的程序代碼，滿足音頻信號(hào)發(fā)生器的大容量存儲(chǔ)要求。
Abstract:
MMC/SD card is more and more widely used in the single chip embedded devices for their excellent performances.This article introduces the application of MMC/SD card as the external power down storage medium in audio signal generator. The extension technology especially for storage of single chip-MMC/SD card via SPI interfaces in 8051F330 single chip, including designs single chip drive program of MMC/SD card based on hardware platform,and also gives the key coding of the program. The implementation of big capacity storage is meaningful in audio signal generator.
介紹了MPC555與CS8900A擴(kuò)展以太網(wǎng)的硬件設(shè)計(jì)圖。以NUCLUES PLUS操作系統(tǒng)為基礎(chǔ)，介紹了網(wǎng)卡軟件驅(qū)動(dòng)程序的編制，給出了以太網(wǎng)協(xié)議包嵌入NUCLEUS PLUS操作系統(tǒng)的實(shí)現(xiàn)方法。
Abstract:
The Ethernet extension hardware design of MPC555 and CS8900A are introduced,and the software driven program based on NUCLEUS PLUS operation system and the technique that Ethernet protocol embedded in NUCLEUS PLUS real operation system are discussed.
The PCA9516 is a BiCMOS integrated circuit intended forapplication in I2C and SMBus systems.While retaining all the operating modes and features of the I2Csystem, it permits extension of the I2C-bus by buffering both the data(SDA) and the clock (SCL) lines, thus enabling five buses of 400 pF.The I2C-bus capacitance limit of 400 pF restricts the number ofdevices and bus length. Using the PCA9516 enables the systemdesigner to divide the bus into five segments off of a hub where anysegment to segment transition sees only one repeater delay.
The PCA9517 is a CMOS integrated circuit that provides level shifting between lowvoltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) I2C-bus or SMBus applications.While retaining all the operating modes and features of the I2C-bus system during thelevel shifts, it also permits extension of the I2C-bus by providing bidirectional buffering forboth the data (SDA) and the clock (SCL) lines, thus enabling two buses of 400 pF. Usingthe PCA9517 enables the system designer to isolate two halves of a bus for both voltageand capacitance. The SDA and SCL pins are over voltage tolerant and arehigh-impedance when the PCA9517 is unpowered.
The PCA9518 is a BiCMOS integrated circuit intended forapplication in I2C and SMBus systems.While retaining all the operating modes and features of the I2Csystem, it permits extension of the I2C-bus by buffering both thedata (SDA) and the clock (SCL) lines, thus enabling virtuallyunlimited buses of 400 pF.
The PCA9519 is a 4-channel level translating I2C-bus/SMBus repeater that enables theprocessor low voltage 2-wire serial bus to interface with standard I2C-bus or SMBus I/O.While retaining all the operating modes and features of the I2C-bus system during thelevel shifts, it also permits extension of the I2C-bus by providing bidirectional buffering forboth the data (SDA) and the clock (SCL) lines, thus enabling the I2C-bus or SMBusmaximum capacitance of 400 pF on the higher voltage side. The SDA and SCL pins areover-voltage tolerant and are high-impedance when the PCA9519 is unpowered.
在現(xiàn)代通信系統(tǒng)中，電話語(yǔ)音的頻帶被限制在300 Hz～4 kHz的范圍內(nèi)，帶來(lái)了語(yǔ)音可懂度和自然度的降低。為了在不增加額外成本的前提下提高語(yǔ)音的可懂度和自然度，進(jìn)行了電話語(yǔ)音頻帶擴(kuò)展的研究。提出了一種改進(jìn)的基于碼本映射的語(yǔ)音帶寬擴(kuò)展算法：在碼本映射的過(guò)程中，使用加權(quán)系數(shù)來(lái)得到映射碼本。客觀測(cè)試結(jié)果表明，用此算法得到的寬帶語(yǔ)音的譜失真度比用一般的碼本映射降低至少2%。主觀測(cè)試結(jié)果表明，用此算法得到的寬帶語(yǔ)音具有更好的可懂度和自然度。
Abstract:
In modern communication systems， the bandwidth of telephone speech is limited from 300Hz to 4 kHz， which reduces the intelligibility and naturalness of speech. Telephone speech bandwidth extension is researched to get wideband speech and to improve its intelligibility and naturalness， without increasing extra costs. This paper put forward an improved algorithm of speech bandwidth extension based on codebook mapping. In the process of codebook mapping， weighted coefficients were used to get mapping codebook. Objective tests show that spectral distortion of wideband speech obtained by this algorithm reduces at least 2%， comparing to conditional codebook mapping. Subjective tests show that the wideband speech obtained by this algorithm has better intelligibility and naturalness.
