DEIF PCM4.3控制通訊板，PCM4.3配置說明
應(yīng)始終清除SLVD16。將SLVD16設(shè)置為1將VMEchip從設(shè)備配置為僅提供D08（EO）和D16數(shù)據(jù)傳輸能力。通常在本地總線只有16位寬。將SLVD16位清除為0配置VMEchip從機提供D08（EO）、D16和D32/UAT數(shù)據(jù)傳輸能力。該位由SYSRESET清除。位5設(shè)置SLVWP位加速VMEbus寫入板載DRAM。
DEIF PCM4.3控制通訊板當設(shè)置SLVWP（從寫過賬）時，VMEbus板載DRAM的寫入周期由VMEchip，然后將數(shù)據(jù)寫入DRAM。這允許VMEbus主機快速結(jié)束其循環(huán)，放置VMEchip完成板載寫入的負擔(dān)DRAM本身。該位由SYSRESET清除。位7將SLVEN設(shè)置為1使其他VMEbus主機能夠訪問MVME147機載DRAM。該位由SYSRESET清除。將ARBTO設(shè)置為1將啟用VMEbus仲裁計時器。這個如果未激活，VMEbus仲裁計時器將激活BBSY*MVME147仲裁器發(fā)出總線授權(quán)后410μs內(nèi)。這個計時器根據(jù)VMEbus中的規(guī)定停用BBSY*規(guī)格這導(dǎo)致仲裁人對任何未決案件進行仲裁請求公共汽車。該位由SYSRESET設(shè)置為1。該寄存器允許軟件配置VMEbus主機必須使用的地址修飾符代碼訪問機載DRAM。寄存器的8位分為三組。至少一個位在每個組中必須設(shè)置，否則地址忽略主控形狀使用的修飾符。地址位7位6位5位4位3位2位1位0FFFE200B超級用戶擴展STND短塊PRGRM數(shù)據(jù)位0-2這三個位構(gòu)成配置從機的第一組AM代碼。將任何位設(shè)置為1使從機能夠響應(yīng)以下示例中所述的循環(huán)。筆記不應(yīng)設(shè)置塊。這些位通過系統(tǒng)重置。位3-5這三個位構(gòu)成第二組。將任何位設(shè)置為1使從機能夠響應(yīng)中所述的周期示例如下。這些位由SYSRESET清除。位6-7這兩個位形成第三組。將任何位設(shè)置為1使從屬設(shè)備能夠響應(yīng)中所述的周期
SLVD16 should always be cleared. Setting SLVD16 to 1
configures the VMEchip slave to provide only D08 (EO) and
D16 data transfer capabilities. It is typically set when the local
bus is only 16 bits wide. Clearing the SLVD16 bit to 0 configures
the VMEchip slave to provide the D08 (EO), D16, and D32/UAT
data transfer capabilities. This bit is cleared by SYSRESET.
Bit 5 Setting the SLVWP bit speeds up VMEbus writes to the onboard
DRAM. When SLVWP (slave write posting) is set, VMEbus
write cycles to the onboard DRAM are acknowledged by the
VMEchip before the data has been written into the DRAM. This
allows the VMEbus master to end its cycle quickly, placing the
burden on the VMEchip to complete the write to onboard
DRAM on its own. This bit is cleared by SYSRESET.
Bit 7 Setting SLVEN to 1 enables other VMEbus masters to access the
MVME147 onboard DRAM. This bit is cleared by SYSRESET. Setting ARBTO to 1 enables the VMEbus arbitration timer. The
VMEbus arbitration timer activates BBSY* if it is not activated
within 410 μs after the MVME147 arbiter issues a bus grant. The
timer deactivates BBSY* as specified in the VMEbus
specification. This causes the arbiter to arbitrate any pending
requests for the bus. This bit is set to 1 by SYSRESET. This register allows software to configure which
address modifier codes the VMEbus masters must use
to access the onboard DRAM. The 8 bits of the register
are organized into three groups. At least one of the bits
in each group must be set, otherwise the address
modifier used by the master is ignored.
ADDRESS BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
FFFE200B SUPER USER EXTED STND SHORT BLOCK PRGRM DATA
R/W R/W R/W R/W R/W R/W R/W R/W
Bits 0-2 These three bits form the first group which configures the slave
AM code. Setting any of the bits to 1 enables the slave to
respond to cycles as described in the example below. Note
BLOCK should never be set. These bits are cleared by
SYSRESET.
