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
Summary of Contents for Am186 CC
Page 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Page 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Page 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Page 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Page 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Page 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Page 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Page 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Page 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...