參數(shù)資料
型號(hào): PDI1394L11
廠商: NXP Semiconductors N.V.
英文描述: 1394 AV Link Layer Controller(AV(音頻/視頻)鏈接層控制器)
中文描述: 1394影音鏈路層控制器(視聽(音頻/視頻)鏈接層控制器)
文件頁(yè)數(shù): 8/46頁(yè)
文件大小: 294K
代理商: PDI1394L11
Philips Semiconductors
Product specification
PDI1394L11
1394 AV link layer controller
1997 Oct 21
8
bytes rather than quadlets the address spaces is 256 bytes,
requiring 8 address lines.
The use of an 8 bit interface introduces an inherent problem that
must be solved: register fields can be more than 8 bits wide and be
used (control) or changed (status) at every internal clock tick. If such
a field is accessed through an 8 bit interface it requires more than
one read or write cycle, and the value should not change in between
to maintain consistency. To overcome this problem accesses to the
chip’s internal register space are always 32 bits, and the host
interface must act as a converter between the internal 32 bit
accesses and external 8 bit accesses. This is where the shadow
registers come in.
12.3.1
To read an internal register the host interface can make a snapshot
(copy) of that specific register which is then made available to the
CPU 8 bits at a time. The register that holds the snapshot copy of
the real register value inside the host interface is called the
read
Read accesses
shadow register
. During a read cycle address lines HIF A0 and
HIF A1 are used to select which of the 4 bytes currently stored in the
read shadow register
is output onto the CPU data bus. This
selection is done by combinatorial logic only, enabling external
hardware to toggle these lines through values 0 to 3 while keeping
the chip in a read access mode to get all 4 bytes out very fast (in a
single extended read cycle), for example into an external quadlet
register.
This solution requires a control line to direct the host interface to
make a snapshot of an internal register when needed, as well as the
internal address of the target register. The register address is
connected to input address lines HIF A2..HIF A7, and the update
control line to input address line HIF A8. To let the host interface
take a new snapshot the target address must be presented on
HIF A2..HIF A7 and HIF A8 must be raised while executing a read
access. The new value will be stored in the
read shadow register
and the selected byte (HIF A0, HIF A1) appears on the output.
SV00803
UPDATE/COPY CONTROL
HIF A8
HIF A2..7
HIF A0..1
CPU
R
8
32
32
32
REGISTERS
TR
Q
Q
MUX
MUX
NOTES:
1. It is not required to read all 4 bytes of a register before reading another register. For example, if only byte 2 of register 0x54 is required a
read of byte address 0x100 + (0
×
54) + 2 = 0x156 is sufficient.
2. The update control line does not necessarily have to be connected to the CPU address line HIF A8. This input could also be controlled by
other means, for example a combinatorial circuit that activates the update control line whenever a read access is done for byte 0. This
makes the internal updating automatic for quadlet reading.
3. Reading the bytes of the read shadow register can be done in any order and as often as needed.
相關(guān)PDF資料
PDF描述
PDI1394L21 Full Duplex AV Link Layer Ccontroller(全雙工AV鏈接層控制器)
PDI1394L41 Content Protection AV Link Layer(內(nèi)容可保護(hù)的AV鏈接層控制器)
PDI1394P21 3-port Physical Layer Interface(三端口物理層接口)
PDI1394P22 3-port Physical Layer Interface(三端口物理層接口)
PDI1394P24 2-port 400 Mbps physical layer interface(2端口 400 Mbps物理層接口)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PDI1394L11BA 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:1394 AV link layer controller
PDI1394L11BA-S 制造商:未知廠家 制造商全稱:未知廠家 功能描述:IEEE 1394 (Firewire) Bus Interface/Controller
PDI1394L21 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:1394 full duplex AV link layer controller
PDI1394L21BE 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:1394 full duplex AV link layer controller
PDI1394L21BP 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:1394 full duplex AV link layer controller