Toshiba TLCS-900/H1 Series Manual page 178

3.9.2 Control registers
The TMP92CF30 MMU has 21 registers. These registers are used for storing seven types of
data (program, read data, write data, source data for DMA channels of odd/even number,
destination-data for DMA channels of odd/even number) for each of three-LOCAL areas
(LOCAL-X through LOCAL-Z). These registers allow for easy data access.
(How to use the control registers)
First, load the control registers for each LOCAL area with the desired bank number and
enable/disable the specified bank. Then, configure the external pins to be used and also the
Memory Controller. Then, when the CPU accesses a logical address in the LOCAL area, the
MMU translates the logical address to the corresponding physical address according to the
programmed bank configuration. The physical address is then placed on the external
address bus pin, which enables external memory accesses. Thus, even when a program
accesses the same logical address, its physical address changes depending on the bank
specified by the program bank register. This enables memory accesses to the different
memory banks.
Note1: When programming the bank registers, the bank area that is overlapping with the COMMON area must not be
specified ( because addresses of those areas are converted to the same physical addresses).
Note2: In the LOCAL area, changing Program bank number (LOCALPX, Y or Z) is disabled. Program bank setting of
each LOCAL area must change in COMMON area. (But bank setting of data-Read and data-Write can change
also in LOCAL area.)
Note3: After setting values specifying the data bank number into bank registers for the read, write and DMA data
(LOCALRn, LOCALWn or LOCALLn, LOCALESn, LOCALEDn, LOCALOSn, LOCALODn; the symbol "n"
indicates X, Y or Z), the specified bank requires a certain setup time to be enabled. Thus, the bank cannot be
accessed by an instruction immediately following the register setting instructions. In this case, insert a dummy
instruction which accesses SFR or another memory area as shown in the following example.
(Example)
Note4: When the LOCAL-Z area is used, pin P82 should be assigned as the chip select signal
works as the chip select signal for the bank 0 through the bank 15, and also for the COMMON-Z area.
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After reset, pin P82 should be properly configured following the procedure below.
(*1) This setting is not required if the COMMON-Z area is not used to store write data.
ld xix, 200000h
ldw (localrx), 8001h
ldw wa, (localrx)
ldw wa, (xix)
ldw (localpz), 8000h
ldw (localrz), 8000h
ldw (localwz), 8000h
ld (P8FC), − − − − − 0 − − B
ld (P8FC2), − − − − − 1 − − B
92CF30-176
;
; Specify the read-data bank number
; ← Inserted dummy instruction which accesses SFR
; instruction which reads bank 1 of the LOCAL-X area.
; Enable the banks in LOCAL-Z for program
; Enable the banks in LOCAL-Z for read data
; Enable the banks in LOCAL-Z for write data (*1)
; Assign P82 as the output
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;
TMP92CF30
. In this case,
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2009-06-12