CHAPTER 4 BUS CONTROL FUNCTION
User’s Manual U13850EJ4V0UM
107
4.2.2 Control register
(1) System control register (SYC)
This register switches control signals for bus interface.
The system control register can be read/written in 8-bit or 1-bit units.
Figure 4-1. System Control Register (SYC)
After reset: 00H
R/W
Address: FFFFF064H
Symbol
7
6
5
4
3
2
1
<0>
SYC
0
0
0
0
0
0
0
BIC
BIC
Bus interface control
0
DSTB, R/W, LBEN, UBEN signal outputs
1
RD, WRL, WRH, UBEN signal outputs
4.3 Bus Access
4.3.1 Number of access clocks
The number of basic clocks necessary for accessing each resource is as follows:
Table 4-2. Number of Access Clocks
Peripheral I/O (bus width)
Bus Cycle Type
Internal ROM
(32 Bits)
Internal RAM
(32 Bits)
Peripheral I/O
(16 Bits)
External Memory
(16 bits)
Instruction fetch
1
3
Disabled
3 + n
Operand data access
3
1
3
3 + n
Remarks 1.
Unit: Clock/access
2.
n:
Number of wait insertions
Содержание MPD703030A
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