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S5335QFAAB 参数 Datasheet PDF下载

S5335QFAAB图片预览
型号: S5335QFAAB
PDF下载: 下载PDF文件 查看货源
内容描述: PCI总线控制器, 3.3V [PCI Bus Controller, 3.3V]
分类和应用: 总线控制器PC
文件页数/大小: 189 页 / 2175 K
品牌: AMCC [ APPLIED MICRO CIRCUITS CORPORATION ]
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Revision 5.01 – November 30, 2005  
S5335 – PCI Bus Controller, 3.3V  
Data Sheet  
8-Bit and 16-Bit Add-On Interfaces  
The following sections discuss the registers associ-  
ated with the mailboxes and accesses required for  
different modes of mailbox operation.  
Some Add-On designs may implement an 8-bit or 16-  
bit bus interface. The mailboxes do not require a 32-bit  
Add-On interface. For 8-bit interfaces, the 8-bit data  
bus may be externally connected to all four bytes of  
the 32-bit Add-On interface (DQ 31:24, 23:16, 15:8,  
7:0 are all connected). The Add-On device reading or  
writing the mailbox registers may access all mailbox  
bytes by cycling through the Add-On byte enable  
inputs. A similar solution applies to 16-bit Add-On  
buses. This solution works for Add-Ons which always  
use just 8-bit or just 16-bit accesses. If the MODE pin  
is high, indicating a 16-bit Add-On interface, the previ-  
ous solution may be modified for an 8-bit interface.  
The difference is that ADR1 must be toggled after the  
first two accesses to steer the S5335 internal data bus  
to the upper 16-bits of the mailboxes.  
Mailbox Status  
Every byte in each mailbox has a status bit in the Mail-  
box Empty/Full Status Registers (MBEF and AMBEF).  
Writing a particular byte into an outgoing mailbox sets  
the corresponding status bit in both the MBEF and  
AMBEF registers. A read of a ‘full’ byte in a mailbox  
clears the status bit. The MBEF and AMBEF are read-  
only. Status bits cannot cleared by writes to the status  
registers.  
The S5335 allows the mailbox status bits to be reset  
through software. The Bus Master Control/Status  
(MCSR) PCI Operation Register and the Add-On Gen-  
eral Control/Status (AGCSTS) Add-On Operation  
Register each have a bit to reset mailbox status. Writ-  
ing a ‘1’ to Mailbox Flag Reset bit in the MCSR or the  
AGCSTS register immediately clears all bits in the  
both the MBEF and AMBEF registers. Writing a ‘0’ has  
no effect. The Mailbox Flag Reset bit is write-only.  
CONFIGURATION  
The PCI interface and the Add-On interface each have  
four incoming mailboxes (IMBx or AIBMx) and four  
outgoing mailboxes (OMBx or AOMBx) along with a  
single mailbox status register (MBEF or AMBEF). Out-  
going mailboxes are read/write, incoming mailboxes  
and the mailbox status registers are read-only.  
The flag bits should be monitored when transferring  
data through the mailboxes. Checking the mailbox sta-  
tus before performing an operation prevents data from  
being lost or corrupted. The following sequences are  
suggested for PCI mailbox operations using status  
polling (interrupts disabled):  
Reading a PCI Incoming Mailbox:  
1. Check Mailbox Status. Read the mailbox status register to determine if any information has been passed from the Add-  
On interface.  
MBEF  
Bits 31:16  
If a bit is set, valid data is contained in the corresponding mailbox  
byte.  
2. Read Mailbox(es). Read the mailbox bytes which MBEF indicates are full. This automatically resets the status bits in  
the MBEF and AMBEF registers.  
IMBx  
Bits  
31:0 Mailbox data.  
Writing a PCI Outgoing Mailbox:  
1. Check Mailbox Status. Read the mailbox status register to determine if information previously written to the mailbox has  
been read by the Add-On interface. Writes to full mailbox bytes overwrite data currently in the mailbox (if not already  
read by the Add-On interface). Repeat until the byte(s) to be written are empty.  
MBEF Bits 15:0 If a bit is set, valid data is contained in the corresponding mailbox byte and has not been read by the  
Add-On.  
2. Write Mailbox(es). Write to the outgoing mailbox byte(s).  
OMBx Bits 31:0 Mailbox data.  
AMCC Confidential and Proprietary  
DS1657 120