User’s Manual
C166S V1 SubSystem
The External Bus Interface
User’s Manual
8-1
V 1.6, 2001-08
8
The External Bus Interface
Although the C166S subsystem supports a powerful set of on-chip peripherals and on-
chip RAM and ROM/OTP/Flash areas, these internal units cover only a small fraction of
the chip’s address space (up to 16 MBytes). The external bus interface allows access to
external peripherals and additional volatile and non-volatile memory. The external bus
interface has a number of possible configurations, so it can be tailored to fit perfectly into
a given application system.
Figure 8-1
SFRs and Port Pins Associated with the External Bus Interface
Accesses to external memory or peripherals are executed by the integrated External Bus
Controller (EBC). The function of the EBC is controlled via the SYSCON, BUSCONx,
and ADDRSELx registers. The BUSCONx registers specify the external bus cycles in
terms of address (mux / demux), data width (16-bit / 8-bit), chip selects, and length
(waitstates / READY control / ALE / RW delay). These parameters are used for accesses
within a specific address area that is defined via the corresponding register ADDRSELx.
The four pairs BUSCON1/ADDRSEL1...BUSCON4/ADDRSEL4 make it possible to
define four independent “address windows”, while all external accesses outside these
windows are controlled via BUSCON0.
P4
BUSCON0
BUSCON1
BUSCON2
ADDRSEL4
P0L / P0H
ADDRSEL1
SYSCON
ODP6
Port 6 Open Drain Control Register
DP6
Port 6 Direction Control Register
P6
Port 6 Data Register
ADDRSELx Address Range Select Register 1...4
BUSCONx
Bus Mode Control Register 0...4
SYSCON
System Control Register
RP0H
Port P0H Reset Configuration Register
Ports & Direction Control
Alternate Functions
Address Registers
Mode Registers
Control Registers
BUSCON3
BUSCON4
ADDRSEL2
RP0H
DP3
P3
ADDRSEL3
P1L / P1H
P6
ODP6E
DP6
A[23:0]
EA
BREQ
CS[4:0]
D[15:0]
RSTIN
HLDA
ALE
READY
HOLD
RD
WR/WRL
BHE/WRH
P0L/P0H
PORT0 Data Registers
P1L/P1H
PORT1 Data Registers
DP3
Port 3 Direction Control Register
P3
Port 3 Data Register
ODP4
Port 4 Open Drain Control Register
P4
Port 4 Data Register
ODP4E
Содержание C166S V1 SubSystem
Страница 10: ...User s Manual C166S V1 SubSystem User s Manual I 6 V 1 6 2001 08...
Страница 16: ...User s Manual C166S V1 SubSystem Introduction User s Manual 1 6 V 1 6 2001 08...
Страница 126: ...User s Manual C166S V1 SubSystem Central Processing Unit User s Manual 3 96 V 1 6 2001 08...
Страница 178: ...User s Manual C166S V1 SubSystem Memory Organization User s Manual 4 52 V 1 6 2001 08...
Страница 206: ...User s Manual C166S V1 SubSystem Instruction Set User s Manual 5 28 V 1 6 2001 08...
Страница 306: ...User s Manual C166S V1 SubSystem Detailed Instruction Set User s Manual 6 100 V 1 6 2001 08...
Страница 362: ...User s Manual C166S V1 SubSystem The External Bus Interface User s Manual 8 40 V 1 6 2001 08...
Страница 452: ...User s Manual C166S V1 SubSystem General Purpose Timer Unit User s Manual 12 44 V 1 6 2001 08...
Страница 454: ...User s Manual C166S V1 SubSystem Instruction Index User s Manual 13 2 V 1 6 2001 08...
Страница 459: ......