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AM79C978KC/W 参数 Datasheet PDF下载

AM79C978KC/W图片预览
型号: AM79C978KC/W
PDF下载: 下载PDF文件 查看货源
内容描述: 单芯片1/10 Mbps的PCI家庭网络控制器 [Single-Chip 1/10 Mbps PCI Home Networking Controller]
分类和应用: 控制器PC
文件页数/大小: 261 页 / 3499 K
品牌: AMD [ AMD ]
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defined after H_RESET, and is  
unaffected by S_RESET and the  
STOP bit.  
BCR48: LED4 Status  
This register defines the functionality of LED4. LED4  
will default to indicating the selected SPEED with Pulse  
stretching enabled (default = 0082h).  
BCR47: OnNow Pattern Matching Register 3  
BCR48 controls the function(s) that the LED4 pin dis-  
plays. Multiple functions can be simultaneously en-  
abled on this LED pin. The LED display will indicate the  
logical OR of the enabled functions.  
Note: This register is used to control and indirectly ac-  
cess the Pattern Match RAM (PMR). When BCR45 is  
written and the PMAT_MODE bit (bit 7) is 1, Pattern  
Match logic is enabled. No bus accesses into PMR are  
possible, and BCR46, BCR47, and all other bits in  
BCR45 are ignored. When PMAT_MODE is set, a read  
of BCR45, BCR46, or BCR47 returns all undefined bits  
except for PMAT_MODE.  
Note: When LEDPE (BCR2, bit 12) is set to 1, pro-  
gramming of the LED2 Status register is enabled.  
When LEDPE is cleared to 0, programming of the  
LED2 register is disabled. Writes to those registers will  
be ignored.  
When BCR45 is written and the PMAT_MODE bit is 0,  
the Pattern Match logic is disabled and accesses to the  
PMR are possible. Bits 6-0 of BCR45 specify the ad-  
dress of the PMR word to be accessed. Following the  
write to BCR45, the PMR word may be read by reading  
BCR45, BCR46 and BCR47 in any order. To write to  
PMR word, the write to BCR45 must be followed by a  
write to BCR46 and a write to BCR47 in that order to  
complete the operation. The RAM will not actually be  
written until the write to BCR47 is complete. The write  
to BCR47 causes all 5 bytes (four bytes of BCR46-47  
and the upper byte of the BCR45) to be written to what-  
ever PMR word is addressed by bits 6:0 of BCR45.  
Note: Bits 15-0 in this register are programmable  
through the EEPROM PREAD operation.  
Bit  
Name  
Description  
31-16 RES  
Reserved locations. Written as  
zeros and read as undefined.  
15  
LEDOUT  
This bit indicates the current  
(non-stretched) value of the LED  
output pin. A value of 1 in this bit  
indicates that the OR of the en-  
abled signals is true.  
When PMAT_MODE is 0, the contents of the word ad-  
dressed by bits 6:0 of BCR45 can be read by reading  
BCR45-47 in any order.  
The logical value of the LEDOUT  
status signal is determined by the  
settings of the individual Status  
Enable bits of the LED register  
(bits 8 and 6-0).  
Bit  
Name  
Description  
31-16 RES  
Reserved locations. Written as  
zeros and read as undefined.  
Read accessible always. This bit  
is read only; writes have no ef-  
fect. LEDOUT is unaffected by  
H_RESET, S_RESET, or STOP.  
15-8 PMR_B4  
Pattern Match RAM Byte 4. This  
byte is written into or read from  
Byte 4 of Pattern Match RAM.  
14  
LEDPOL  
LED Polarity. When this bit has  
the value 0, then the LED pin will  
be driven to a LOW level whenev-  
er the OR of the enabled signals  
is true, and the LED pin will be  
disabled and allowed to float high  
whenever the OR of the enabled  
signals is false (i.e., the LED out-  
put will be an Open Drain output  
and the output value will be the  
inverse of the LEDOUT status  
bit).  
These bits are read and write ac-  
cessible always. PMR_B4 is un-  
defined after H_RESET, and is  
unaffected by S_RESET and the  
STOP bit.  
7-0  
PMR_B3  
Pattern Match RAM Byte 3. This  
byte is written into or read from  
Byte 3 of Pattern Match RAM.  
These bits are read and write ac-  
cessible always. PMR_B3 is un-  
defined after H_RESET, and is  
unaffected by S_RESET and the  
STOP bit.  
When this bit has the value 1,  
then the LED pin will be driven to  
a HIGH level whenever the OR of  
the enabled signals is true, and  
the LED pin will be driven to a  
LOW level whenever the OR of  
the enabled signals is false (i.e.,  
176  
Am79C978