8-Bit Bus With Fixed Wait States, In Synchronous Mode And In Address/Data Separate Mode; Fig. 8-13-10 Access Timing On A 8-Bit Bus With Fixed Wait States, In Synchronous Mode And In Address/Data Separate Mode (Mclk = Sysclk Multiplied By 4) - Panasonic MN103001G/F01K User Manual

Bus Controller (BC)

8.13.4 8-bit Bus with Fixed Wait States, in Synchronous Mode and in Address/Data Separate Mode

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.
In synchronous mode, the bus access starts in synchronization with SYSCLK, and when fixed wait states are
inserted, the access ends according to the timing that was set in the memory control register.
The various parameters for external memory access are set in memory control registers 0 to 3, corresponding to
each block.
Fig. 8-13-10 is the timing chart in the case of a half-word access using an "8-bit bus with fixed wait states, in
synchronous mode, in address/data separate mode, and with the frequency of MCLK equal to that of SYSCLK
multiplied by four."
Fig. 8-13-11 is the timing chart in the case of a half-word access using an "8-bit bus with fixed wait states, in
synchronous mode, in address/data separate mode, and with the frequency of MCLK equal to that of SYSCLK
multiplied by two."
Fig. 8-13-12 is the timing chart in the case of a half-word access using an "8-bit bus with fixed wait states, in
synchronous mode, in address/data separate mode, and with the frequency of MCLK equal to that of SYSCLK."
Note that when writing, WE0 is asserted and the data is output on D7 to 0.
Note: For details on the mode settings, refer to Table 8-9-1, "Mode Settings by the BC External Pins."
MCLK
SYSCLK
BCS BCS
BCS BCS
BCE BCE BCE BCE
An
A[0]=0 A[0]=1 A[0]=0 A[0]=1
CSn
REN REN
RE
EA
EA
WEN WEN
WE0
EA
EA
D7-0
Read high- Write high-
Read low- Write low-
order side
order side
order side order side
: Undefined
Fig. 8-13-10 Access Timing on a 8-bit Bus with Fixed Wait States, in Synchronous Mode and in
Address/Data Separate Mode (MCLK = SYSCLK multiplied by 4)
For details on the various timing settings, refer to the description of the memory control register in section 8.6,
"Description of Registers."
8-39