Chip Selects
5-6
Am186™CC/CH/CU Microcontrollers User’s Manual
5.5.2.4
PCS7–PCS0
The Am186CC/CH/CU microcontrollers each provide eight chip selects for eight
contiguous, user-locatable, 256-byte address ranges within memory or I/O space. The base
address can reside anywhere in the 1-Mbyte memory address space as long as it is a
multiple of 2 Kbytes (0 is a valid multiple), and the memory space is not already mapped
to by UCS, LCS, or MCS. (The PCS address range can overlap the UCS or LCS address
ranges if they are mapped to DRAM.) The PCS chip selects can also access the 64-Kbyte
I/O space, as long as the base address is a multiple of 2 Kbytes.
The PCS chip selects are programmable with two registers. The BA bit field of the PACS
register sets the base address (0 is a valid address).
If the chip selects are programmed
to reside in the CPU’s I/O space, bits BA[19–16] are forced to 0 by hardware, as the upper
bound of the CPU’s I/O space is 64 Kbytes. The MS bit in the MPCS register determines
whether PCS chip selects are mapped to memory or I/O space.
Figure 5-2
Chip Selectable Memory Space
8-, 16-, 32-,
64-, 128-,
256-, or
512-Kbyte
Block
1-Mbyte
Memory
Space
FFFFFh
00000h
80000h
7FFFFh
UCS Selectable
64-, 128-,
256-, or
512-Kbyte
Block
LCS Selectable
MCS3–MCS0
Selectable
C0000h
E0000h
64-, 128-,
256-, or
512-Kbyte
Block
0FFFFh
1FFFFh
3FFFFh
Base
1
Base + 8K
Base + 16K
Base + 32K
Base + 64K
Base + 128K
Base + 256K
Base + 512K
Notes:
1. Base must be an integer multiple of the block size and can be anywhere in memory space from 00000h to FDFFFh,
as long as memory space is not already mapped to by UCS, LCS, or PCS.
2. Base must be a multiple of 2 Kbytes and PCS memory region must not be configured to overlap with MCS space
or non-DRAM LCS or UCS space.
FFFFFh
FFFFFh
00000h
00000h
PCS7–PCS0
Selectable
Base
2
Base + 2047 bytes
FFFFFh
00000h
8 Contiguous
256-Byte
Address
Regions
F0000h
Содержание Am186 CC
Страница 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Страница 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Страница 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Страница 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Страница 39: ...Architectural Overview Am186 CC CH CU Microcontrollers User s Manual 1 15 Figure 1 6 32 Channel Linecard CH CC...
Страница 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Страница 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Страница 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Страница 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Страница 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...