AM79C976 Advanced Micro Devices, AM79C976 Datasheet - Page 126

• Manufacturer Part Number: AM79C976
• Description: PCnet-PRO 10/100 Mbps PCI Ethernet Controller
• Manufacturer: Advanced Micro Devices

AUTOPOLL3:
Offset 08Eh
This register controls the automatic polling of a user-
selectable external PHY register, AP_REG3.
126
14-13
12-8
Bit
4-0
15
7
6
5
AP_REG3_ADDR
AP_PHY3_ADDR
AP_PHY3_DFLT
AP_PRE_SUP3
AP_REG3_EN
Auto-Poll3 Register
Name
RES
RES
Enable Bit for Autopoll Register 3. When this bit and the Auto-Poll External PHY bit (APEP) in
CMD1 are both set to 1, the Auto-Poll State Machine periodically reads the external PHY register
selected by the AP_PHY3_ADDR and AP_REG3_ADDR fields and sets the APINT3 interrupt bit
if it detects a change in the register’s contents.
Reserved locations. Written as zeros and read as undefined.
AP_REG3 Address. This field contains the register number of an external PHY register that the
Auto-Poll State Machine will periodically read if the AP_REG3_EN bit in this register and the
APEP bit (CMD3, bit 24) is set.
Reserved location. Written as zero and read as undefined.
Auto-Poll Preamble Suppression. If this bit is set to 1, the Auto-Poll State Machine will suppress
the preambles of the MII Management Frames that it uses to periodically read the external PHY
register selected by the AP_PHY3_ADDR and AP_REG3_ADDR fields.
This bit is ignored when the AP_PHY3_DFLT bit is set.
Auto-Poll PHY3 Default. When this bit is set, the Auto-Poll State Machine ignores the contents of
the AP_PHY3_ADDR and AP_PRE_SUP3 fields and uses the AP_PHY0_ADDR field for the
address of the PHY device to be polled. If this bit is set, the Auto-Poll State Machine will suppress
preambles only if the Port Manager has determined that the default external PHY can accept MII
Management Frames without preambles. (The Port Manager examines bit 6 in register 1 of the
default PHY to make this determination.)
Auto-Poll PHY3 Address. This field contains the address of the external PHY that contains
AP_REG3.
This bit is ignored when the AP_PHY3_DFLT bit is set.
Table 35. AUTOPOLL3:
P R E L I M I N A R Y
Am79C976
All bits in this register are set to their default values by
H_RESET. All bits are also set to their default values
before EEPROM data are loaded or after an EEPROM
read failure.
The default value for all bits in this register is 0.
Auto-Poll3 Register
Description
8/01/00