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Bus Controller (BC)
8-60
8.13.12
8-bit Bus in Asynchronous Mode and in Address/Data Multiplex Mode
By setting the mode through the MMOD1 and 0 pins and the EXMOD1 and 0 pins, blocks 0 to 3 use multiplex pins
for the memory address and memory data signals (pins ADM15 to 0).
8-bit bus mode is set for block 0 by setting the mode through the MMOD1 and 0 pins and the EXMOD1 and 0 pins,
and for blocks 1 to 3 by setting the BnBW bit to “0” in the corresponding memory control register. In 8-bit bus
mode, half-word access (16 bits) is performed by means of two external accesses, with A[0] = “0” for the low-order
byte and A[0] = “1” for the high-order byte. Word access (32 bits) is performed by means of four accesses, with
A[1:0] = “00”, A[1:0] = “01”, A[1:0] = “10”, and A[1:0] = “11”, starting from the low-order side. Note that the
low-order 8 bits (D7 to 0) are used for the data bus.
Asynchronous mode is used for accessing external memory at high speed; the address signals, CSn signals, etc., are
output asynchronously with SYSCLK but in synchronization with the internal MCLK. In asynchronous mode,
accesses are all by fixed wait insertion.
The various parameters for external memory access are set in memory control registers 0 to 3, corresponding to
each block.
Fig. 8-13-30 is the timing chart in the case of a half-word access using an “8-bit bus in asynchronous mode, in
address/data multiplex mode.”
As shown in each timing chart, the ADM15 to 0 pins go to “Hi-Z” or the undefined output state while CSn is
negated in address/data multiplex mode. When the bus authority is released, the ADM15 to 0 pins are either pulled
up or go to “Hi-Z”, depending on the setting of the I/O port output mode register.
Note that when writing, WE0 is asserted and the data is output on ADM7 to 0.
Note: For details on the mode settings, refer to Table 8-9-1, “Mode Settings by the BC External Pins.”
Note: “0” (low level) is output on pins A23 to 16 (A23 also serves as CS3) while the ADM15 to 0 pins function as
data pins. Therefore, refer to 3. in section 8.16, “Cautions,” regarding the use of these pins.
Summary of Contents for MN103001G/F01K
Page 1: ...MICROCOMPUTER MN1030 MN103001G F01K LSI User s Manual Pub No 23101 050E ...
Page 2: ......
Page 4: ......
Page 6: ......
Page 8: ......
Page 9: ...Table of Contents List of Figures and Tables 0 ...
Page 26: ...xviii ...
Page 27: ...1 0 1 General Specifications ...
Page 35: ...2 CPU 2 ...
Page 57: ...3 Extension Instruction Specifications 3 ...
Page 96: ...Extension Instruction Specifications 3 40 ...
Page 97: ...4 Memory Modes 3 4 ...
Page 102: ...Memory Modes 4 6 ...
Page 103: ...5 Operating Mode 5 ...
Page 107: ...6 Clock Generator 6 13 ...
Page 111: ...7 Internal Memory 7 ...
Page 114: ...Internal Memory 7 4 ...
Page 115: ...8 Bus Controller BC 8 ...
Page 189: ...9 Interrupt Controller 9 ...
Page 220: ...Interrupt Controller 9 32 ...
Page 221: ...10 8 bit Timers 9 10 ...
Page 254: ...8 bit Timers 10 34 ...
Page 255: ...11 16 bit Timers 11 ...
Page 292: ...16 bit Timers 11 38 ...
Page 293: ...12 Watchdog Timer 11 12 ...
Page 302: ...Watchdog Timer 12 10 ...
Page 303: ...13 Serial Interface 13 ...
Page 354: ...Serial Interface 13 52 ...
Page 355: ...14 A D Converter 14 ...
Page 367: ...15 I O Ports 15 ...
Page 431: ...16 Internal Flash Memory 16 ...
Page 439: ...17 17 Ordering Mask ROM ...
Page 442: ...Ordering Mask ROM 17 4 ...
Page 443: ...Appendix ...