AMD
P R E L I M I N A R Y
SIR0: General Configuration Register (GCR)
This register is used to control general functions related
to the Am79C930, particularly interrupts to and from the
80188 core and power down functions.
Bit
Name
Reset Value
Description
7
SWRESET
0
Software Reset. When SWRESET is set to a 1, the BIU will be
RESET, with the exception of the SWRESET bit and the software
reset bit in the PCMCIA Card Configuration Register. The 80188
embedded controller will not be reset. TAI will not be reset.
SWRESET is unaffected by the RESET bit of the PCMCIA Configu-
ration Option Register.
6
CORESET
0
Core Reset. When CORESET is set to a 1, the 80188 embedded
controller and the TAI are held in RESET. In addition, the
FLASHWAIT and SRAMWAIT fields of MIR8 and MIR9 are set to
their default states of “11b” The reset to the 80188 core and the TAI
remains active as long as CORESET has the value 1. During the
reset time, the Am79C930 memory interface bus is directly acces-
sible through the system interface.
5
4
DISPWDN
ECWAIT
0
0
Disable Power Down Mode. When DISPWDN is set to a 1, the
Am79C930 device will be prevented from entering the power down
mode. If the Am79C930 device is already in the power down mode
when DISPWDN notes a transition from 0 to 1, then the power down
mode will be exited within three CLKIN periods.
Embedded Controller WAIT Mode. When ECWAIT is set to 1, the
RDY input to the 80188 core will be held deasserted forcing the
80188 core into a WAIT state. At the same time, the system inter-
face side of the BIU will be placed into direct access mode, such
that system interface access cycles will have direct access to the
Am79C930 memory interface. When ECWAIT is reset to a 0, the
RDY line to the 80188 core will be reasserted, the 80188 core
will resume operation and system interface direct access mode will
cease. ECWAIT also functions to determine the source of
interrupts to the system (through the system interface interrupt
pin(s)) as follows:
ECWAIT
(SIR0[4])
Source of Interrupts
Sent To System
0
MIR0[2] (note that this bit
is set by 80188 firmware)
1
TAI interrupt
3
ECINT
0
Embedded Controller Interrupt. ECINT indicates that an interrupt
for the system has been generated by either the 80188 core or the
TAI. Only one interrupt source is operable at one time. The oper-
able interrupt source is determined by the setting of the 80188
WAIT mode bit (SIR0[4]). This bit will stay set until the driver soft-
ware clears the interrupt by writing a 1 to this bit.
Am79C930
77
AMD [ AMD ]
