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CS8900A 参数 Datasheet PDF下载

CS8900A图片预览
型号: CS8900A
PDF下载: 下载PDF文件 查看货源
内容描述: 水晶局域网? ISA以太网控制器 [Crystal LAN ⑩ ISA Ethernet Controller]
分类和应用: 控制器局域网以太网
文件页数/大小: 128 页 / 1360 K
品牌: CIRRUS [ CIRRUS LOGIC ]
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CS8900A  
Crystal LAN™ ISA Ethernet Controller  
’C46 or ’CS46. If EEDI is high, the EEPROM is a  
’C56, ’CS56, ’C66, or ’CS66.  
stored to its default. Once initialization is complete  
(configuration loaded from EEPROM or reset to  
default configuration) the INITD bit is set (Register  
16, SelfST, bit 7).  
3.4.7.2 Loading Configuration Data  
The CS8900A reads in the first word from the EE-  
PROM to determine if configuration data is con-  
tained in the EEPROM. If configuration data is not  
stored in the EEPROM, the CS8900A terminates  
initialization from EEPROM and operates using its  
default configuration (See Table 3). If configura-  
tion data is stored in EEPROM, the CS8900A auto-  
matically loads all configuration data stored in the  
Reset Configuration Block into its internal Pack-  
etPage registers.  
3.5 Programming the EEPROM  
After initialization, the host can access the EE-  
PROM through the CS8900A by writing one of  
seven commands to the EEPROM Command regis-  
ter (PacketPage base + 0040h). Figure 5 shows the  
format of the EEPROM Command register.  
3.5.1 EEPROM Commands  
The seven commands used to access the EEPROM  
are: Read, Write, Erase, Erase/Write Enable,  
Erase/Write Disable, Erase-All, and Write-All.  
They are described in Table 7.  
3.4.8 EEPROM Read-out Completion  
Once all the configuration data are transferred to  
the appropriate PacketPage registers, the CS8900A  
performs a checksum calculation to verify the Re-  
set Configuration Blocks data are valid. If the re-  
sulting total is 0, the read-out is considered valid.  
Otherwise, the CS8900A initiates a partial reset to  
restore the default configuration.  
3.5.2 EEPROM Command Execution  
During the execution of a command, the two Op-  
code bits, followed by the six bits of address (for a  
’C46 or ’CS46) or eight bits of address (for a ’C56,  
’CS56, ’C66 or ’CS66), are shifted out of the  
CS8900A, into the EEPROM. If the command is a  
Write, the data in the EEPROM Data register  
(PacketPage base + 0042h) follows. If the com-  
mand is a Read, the data in the specified EEPROM  
If the read-out is valid, the EEPROMOK bit (Reg-  
ister 16, SelfST, bit A) is set. EEPROMOK is  
cleared if a checksum error is detected. In this case,  
the CS8900A performs a partial reset and is re-  
AD7 - AD0 used with ’C56,  
’CS56, ’C66 and ’CS66  
F
X
E
X
D
X
C
X
B
X
A
9
8
7
6
5
4
3
2
1
0
ELSEL OP1 OP0 AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0  
AD5 - AD0 used with  
’C46 and ’CS46  
Bit  
[F:B]  
[A]  
Name  
Description  
Reserved  
ELSEL  
External Logic Select: When clear, the EECS pin is used to select the EEPROM.  
When set, the ELCS pin is used to select the external LA decode circuit.  
[9:8]  
[7:0]  
OP1, OP0  
Opcode: Indicates what command is being executed (see next section).  
AD7 to AD0 EEPROM Address: Address of EEPROM word being accessed.  
Figure 5. EEPROM Command Register Format  
CIRRUS LOGIC PRODUCT DATA SHEET  
24  
DS271PP3