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P R E L I M I N A R Y
The SRAM is intended to serve as a shared memory re-
source between the driver operating through the system
interface and the 80188 core operating through the
Am79C930 memory interface bus. Even though SRAM
memory locations 0 0400h through 0 043Fh are acces-
sible from the system interface, these locations cannot
be used for driver-firmware shared memory functions,
since they are inaccessible from the 80188 core.
visible as common memory. The upper 32 bytes of the
2K of attribute memory space must not be used for
PCMCIA CIS information, since these bytes map to the
upper 16 bytes of the Flash memory, which will be used
bythe80188coreoftheAm79C930astheinitialinstruc-
tion locations after reset.
Note that the Configuration Tuple must contain the
value 800h for the TPCC_RADR field, since the Card
Configuration Registers within the Am79C930 device
are located at this fixed offset.
PCMCIA Attribute Memory Resources
— The
PCMCIA standard requires that each PCMCIA device
contain a Card Information Structure (CIS). The CIS
contains information that is used to provide possible
configuration options to the system.
The PCMCIA Card Configuration registers that are sup-
ported are the Configuration Option Register and the
CardConfigurationandStatusRegister. Thesetworeg-
isters are physically located in the Bus Interface Unit
and logically exist only in PCMCIA Attribute Memory
space. They are located at Attribute Memory locations
0800h and 0802h, respectively. The location of these
registers is fixed. Therefore, the information pro-
grammed into the CIS must give the value 2K (=0800h)
as the Card Configuration Registers Base Address in
the TPCC_RADR field of the Configuration Tuple.
The PCMCIA standard requires that the first tuple of the
CIS should be located at Attribute memory byte 0h. 1K
of Flash memory space is mapped into the lowest 2K of
PCMCIA attribute memory space to accommodate this
requirement. Since odd addressed bytes of Attribute
memory are undefined, these addresses are not
mapped to the Flash memory. The 1K of Flash memory
space that is mapped to Attribute memory space is also
Am79C930 Device PCMCIA Mode Attribute Memory Map
PCMCIA Address
in Attribute Memory
SIR1[5:3]
Size of Space
Physical Memory
0000h – 07FFh
(even values only)
XXX*
2 Kbytes
Flash Memory 1 FC00h – 1 FFFFh
(only 1 K of Flash memory is
allocated, since odd addressed
PCMCIA attribute memory locations
are undefined)
0800h
XXX*
1 byte
Configuration Option Register
in BIU
0801h
0802h
XXX*
XXX*
1 byte
1 byte
Device responds with undefined data
Card Configuration and Status
Register in BIU
0803h
XXX*
XXX*
1 byte
Device responds with undefined data
0804h – 7FFFh
30K–2 bytes
Device may respond to these
addresses. See note below.
*XXX = Don’t care
Note: Device will respond to any address in which A11 is equal to 1 andREG, OE, and CE1 are asserted.
The only writable PCMCIA Attribute memory locations
are the two Card Configuration Registers at Attribute
Memory locations 800h and 802h. These two registers
do not correspond to Flash memory locations. These
two registers are physically located inside of the BIU
section of the Am79C930 device. Attribute memory
locations 0000h–07FFh are mapped directly to Flash
memory and are, therefore, read-only locations. Note
that the 2K space of attribute memory 0000h–07FFh are
mapped to 1K of Flash memory space. Since PCMCIA
defines that only even addressed bytes of Attribute
memory are defined to exist, only the even
addressed 1K of the 2K attribute space is actually
physically present.
Some of the Am79C930 device’s PCMCIA Attribute
Memory locations have predefined uses and, therefore,
are not freely available to the device driver. The follow-
ing table indicates restricted space within PCMCIA At-
tribute Memory map of the Am79C930 device.
Am79C930
61
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