公开(公告)号：US20100306426A1

公开(公告)日：2010-12-02

申请号：US12599062

申请日：2008-05-14

Applicant: Johannes Boonstra ,  Sundaravaradan Rangarajan ,  Rajendra Kumar

Inventor： Johannes Boonstra ,  Sundaravaradan Rangarajan ,  Rajendra Kumar

IPC: G06F5/14

CPC classification number: G06F5/12

Abstract: A FIFO memory circuit is for interfacing between circuits with different clock domains. The circuit has a FIFO memory (10), a write pointer circuit (16) clocked by the clock of a first clock domain and controlling the memory location to which data is written, and a read pointer circuit clocked by the clock of a second clock domain and controlling the memory location from which data is read. The read and write pointer circuits use gray coding. The memory circuit further comprises a duplicate write pointer circuit (30) which has its write pointer address incremented synchronously with the write pointer circuit (16), and which has a starting write address selected such that the duplicate write pointer address lags behind the write pointer address circuit by a number of address locations corresponding to the size of the FIFO memory (10). A comparator (34) compares the read pointer circuit address with the duplicate write pointer circuit address for determining a full status of the FIFO memory.

Abstract translation: FIFO存储器电路用于在具有不同时钟域的电路之间进行接口。 电路具有FIFO存储器（10），由第一时钟域的时钟定时并且控制写入数据的存储器位置的写指针电路（16）以及由第二时钟的时钟脉冲定时的读指针电路 并控制读取数据的存储器位置。 读写指针电路采用灰度编码。 存储器电路还包括一个重写写指针电路（30），它具有与写指针电路（16）同步增加的写指针地址，并且具有选择的开始写地址，使得重写写指针地址落在写指针后面 地址电路由与FIFO存储器（10）的大小对应的多个地址位置。 比较器（34）将读取指针电路地址与用于确定FIFO存储器的完整状态的重复写指针电路地址进行比较。

公开(公告)号：US08612651B2

公开(公告)日：2013-12-17

申请号：US12599062

申请日：2008-05-14

Applicant: Johannes Boonstra ,  Sundaravaradan Rangarajan ,  Rajendra Kumar

Inventor： Johannes Boonstra ,  Sundaravaradan Rangarajan ,  Rajendra Kumar

IPC: G06F3/00 ,  G06G5/00

CPC classification number: G06F5/12

Abstract: A FIFO memory circuit is for interfacing between circuits with different clock domains. The circuit has a FIFO memory (10), a write pointer circuit (16) clocked by the clock of a first clock domain and controlling the memory location to which data is written, and a read pointer circuit clocked by the clock of a second clock domain and controlling the memory location from which data is read. The read and write pointer circuits use gray coding. The memory circuit further comprises a duplicate write pointer circuit (30) which has its write pointer address incremented synchronously with the write pointer circuit (16), and which has a starting write address selected such that the duplicate write pointer address lags behind the write pointer address circuit by a number of address locations corresponding to the size of the FIFO memory (10). A comparator (34) compares the read pointer circuit address with the duplicate write pointer circuit address for determining a full status of the FIFO memory.

Abstract translation: FIFO存储器电路用于在具有不同时钟域的电路之间进行接口。 电路具有FIFO存储器（10），由第一时钟域的时钟定时并且控制写入数据的存储器位置的写指针电路（16）以及由第二时钟的时钟脉冲定时的读指针电路 并控制读取数据的存储器位置。 读写指针电路采用灰度编码。 存储电路还包括一个重写写指针电路（30），它具有与写指针电路（16）同步增加的写指针地址，并且具有选择的开始写地址，使得重写写指针地址落在写指针之后 地址电路由与FIFO存储器（10）的大小对应的多个地址位置。 比较器（34）将读取指针电路地址与用于确定FIFO存储器的完整状态的重复写指针电路地址进行比较。