AM79C976 Advanced Micro Devices, AM79C976 Datasheet - Page 188

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

Bit
31-0
Bit
31-16
15-0 TXPOLLINT Transmit Polling Interval. This
188
Name
RES
Name
RES
Read/Write accessible. These
bits are unaffected by H_RESET,
S_RESET, or STOP.
zeros and read as undefined.
zeros and read as undefined.
register contains the time that the
Am79C976 controller will wait be-
tween successive polling opera-
tions. The TXPOLLINT value is
expressed as the two’s comple-
ment of the desired interval,
where each bit of TXPOLLINT
represents 1 PCI clock period.
TXPOLLINT[3:0]
(TXPOLLINT[16] is implied to be
a one, so TXPOLLINT[15] is sig-
nificant and does not represent
the sign of the two’s complement
TXPOLLINT value.)
The default value of this register
is 0000h. This corresponds to a
polling interval of 65,536 clock
periods
CLK = 33 MHz).
Setting the INIT bit starts an ini-
tialization process that sets TX-
POLLINT to its default value. If
the user wants to program a val-
ue for TXPOLLINT other than the
default, then he must change the
value after the initialization se-
quence has completed.
If the user does not use the initial-
ization block to initialize the
Am79C976 device, but instead,
chooses to write directly to each
of the registers that are involved
in the INIT operation, then it is im-
perative that the user also writes
an acceptable value to CSR47 as
part of the alternative initialization
sequence.
Reserved locations. Written as
Reserved locations. Written as
Description
Description
(1.966
are
ms
P R E L I M I N A R Y
ignored.
when
Am79C976
Bit
31-0
Bit
31-16 RES
15-0
Name
RES
Name
CHPOLLINT Chain Polling Interval. This regis-
Read/Write accessible. These
bits are unaffected by H_RESET,
S_RESET, or STOP.
The default value of this register
is 0000h. This corresponds to a
polling interval of 65,536 clock
periods
CLK = 33 MHz).
Setting the INIT bit starts an ini-
tialization
CHPOLLINT to its default value.
If the user wants to program a
value for CHPOLLINT other than
the default, then he must change
the value after the initialization
sequence has completed.
If the user does not use the initial-
ization block to initialize the
Am79C976 device, but instead,
chooses to write directly to each
of the registers that are involved
in the INIT operation, then it is im-
perative that the user also writes
an acceptable value to CSR49 as
zeros and read as undefined.
zeros and read as undefined.
ter contains the time that the
Am79C976 controller will wait be-
tween successive polling opera-
tions
Management Unit is in the middle
of a buffer chaining operation.
The CHPOLLINT value is ex-
pressed as the two’s complement
of the desired interval, where
each bit of CHPOLLINT approxi-
mately represents one PCI clock
time period. CHPOLLINT[3:0] are
ignored. (CHPOLLINT[16] is im-
plied to be a 1, so CHPOL-
LINT[15] is significant and does
not represent the sign of the two’s
complement CHPOLLINT value.)
Description
Reserved locations. Written as
Description
Reserved locations. Written as
when
(1.966
process
the
ms
that
8/01/00
Buffer
when
sets