參數(shù)資料
型號: NSAM266SA
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 數(shù)字信號處理
英文描述: 4 Mbit Uniform Sector, Serial Flash Memory
中文描述: 8-BIT, MIXED DSP
文件頁數(shù): 31/52頁
文件大小: 571K
代理商: NSAM266SA
2.0 Software
(Continued)
4. When a return value is transmitted, the MWRDY signal is
deactivated after every byte, and activated again when
the CompactSPEECH is ready to send another byte, or to
receive a new command.
The MWRDY signal is activated (cleared to 0) after reset,
and after a protocol time-out. (See Section 2.12.2.)
The MWRQST signal is used as follows:
1. The MWRQST signal is activated (cleared to 0), when the
status word is changed.
2. The MWRQST signal remains active (0), until the
CompactSPEECH receives a GSW command.
Figure 2-5 illustrates the sequence of activities during a
MICROWIRE data transfer.
2.12.2 Interface Protocol Error Handling
Interface Protocol Time-Outs
Depending on the CompactSPEECH’s state, if more than
20 ms–30 ms elapse between two consecutive byte trans-
missions, or two byte receptions, within the same command
or return value, after the MWRDY signal is asserted, a time-
out event occurs, and the CompactSPEECH responds as
follows:
1. Sets the error bit in the status word to 1.
2. Sets the EVDTIMEOUT bit in the error word to 1.
3. Activates the MWRQST signal (clears it to 0).
4. Activates the MWRDY signal (clears it to 0).
5. Waits for a new command. (After a time-out occurs, the
microcontroller must wait at least four milliseconds before
issuing the next command.)
Echo Mechanism
The CompactSPEECH echoes back to the microcontroller
all the bits received by the CompactSPEECH. Upon detec-
tion of an error in the echo, the microcontroller should stop
the protocol clock, which eventually causes a time-out error
(i.e., ERRDTIMEOUT bit is set in the error word).
Note:
When a command has a return value, the CompactSPEECH transmits
bytes of the return value instead of the echo value.
The CompactSPEECH transmits a byte as an echo when it
receives the value 0xAA from the microprocessor. Upon de-
tection of an error the CompactSPEECH activates the
MWRQST signal, and sets the ERRDCOMM bit in the error
word.
2.13 THE MASTER MICROWIRE INTERFACE
The CompactSPEECH’s Master MICROWIRE controller im-
plements the MICROWIRE/PLUS interface in master mode.
It enables the CompactSPEECH to control flash devices.
Several devices may share the Master MICROWIRE chan-
nel. This can be implemented by connecting device selec-
tion signals to general purpose output ports.
2.13.1 Master MICROWIRE Data Transfer
The Signals
The Master MICROWIRE controller’s signals are the Master
MICROWIRE serial CLocK (MMCLK), the Master MICRO-
WIRE serial Data OUT (MMDOUT) signal and the Master
MICROWIRE serial Data In (MMDIN) signal.
The Master MICROWIRE controller can handle up to four
flash devices. The CompactSPEECH uses the signals,
CS0–CS3, as required for the number of devices in use, as
device chip-select signals.
The Clock for Master MICROWIRE Data Transfer
Before data can be transferred, the transfer rate must be
determined and set. The rate of data transfer on the Master
MICROWIRE is determined by the Master MICROWIRE se-
rial CLocK (MMCLK) signal. This rate is the same as the
Codec CLocK (CCLK) signal. As long as the Master MICRO-
WIRE is transferring data, the codec interface must be en-
abled and its sampling rate should not be changed.
TL/EE/12584–29
FIGURE 2-5. Sequence of Activities during a MICROWIRE Byte Transfer
http://www.national.com
31
相關PDF資料
PDF描述
NSAM266SAA 4 Mbit Uniform Sector, Serial Flash Memory
NSB8 BASIC interpreter for Z80 family
NSB9435T1 High Current Bias Resistor Transistors(高強度電流偏置電阻晶體管)
NSBA114EDXV6T1 Dual Bias Resistor Transistors(雙偏置電阻晶體管)
NSBA114YDXV6T1 Dual Bias Resistor Transistors(雙偏置電阻晶體管)
相關代理商/技術參數(shù)
參數(shù)描述
NSAM266SAA 制造商:NSC 制造商全稱:National Semiconductor 功能描述:NSAM266SA CompactSPEECHTM Digital Speech Processor with Serial Flash Interface
NSAM266SAA/V 制造商:NSC 制造商全稱:National Semiconductor 功能描述:NSAM266SA CompactSPEECHTM Digital Speech Processor with Serial Flash Interface
NSAM266SAA/VLJ 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Solid-State Recorder
NSAM266SC 制造商:未知廠家 制造商全稱:未知廠家 功能描述:
NSAM266SCA/V 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Solid-State Recorder