UPD75236GJ データシートの表示（PDF） - NEC => Renesas Technology
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UPD75236GJ Datasheet PDF : 190 Pages
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µPD75236
3. INTERNAL CPU FUNCTIONS
3.1 PROGRAM COUNTER (PC): 14 BITS
This is a 14-bit binary counter to hold the program memory address information.
Fig. 3-1 Program Counter Configuration
PC13 PC12 PC11 PC10 PC9 PC8 PC7 PC6 PC5 PC4 PC3 PC2 PC1 PC0
When RESET is input, the lower 6 bits at address 0000H and the contents at address 0001H of the program
memory are set to PC13 to PC8 and PC7 to PC0, respectively, and the PC is initialized.
3.2 PROGRAM MEMORY (ROM): 16256 WORDS × 8 BITS
This is a mask programmable ROM having a configuration of 16256 words × 8 bits to store programs, table
data, etc.
The program memory is addressed by the program counter. Table data can be referred to by the table
reference instruction (MOVT).
The branch range enabled by the branch and subroutine call instructions is shown in Fig. 3-2. The relative
branch instruction (BR $addr) enables branch to the [PC contents –15 to –1, +2 to +16] address irrespective of
the block boundary.
The program memory addresses are 0000H-3F7FH and the following addresses are especially assigned. (All
areas except 0000H and 0001H can be used as the normal program memory.)
• Addresses 0000 and 0001H
Vector address table for writing the program start address to be set upon RESET input and the RBE and
MBE set values. Can be reset and started at any address in a 16K space (0000H to 3F7FH).
• Addresses 0002 to 000FH
Vector address table for writing the program start address to be set by each vectored interrupt and the
RBE and MBE set values. Interrupt service can be started at any address in a 16K space (0000H to 3F7FH).
• Addresses 0020 to 007FH
Table area to be referred to by GETI instruction*.
* GETI instruction is an instruction to realize any 2-byte/3-byte instruction or two 1-byte instructions with one
byte. It is used to decrease the number of program bytes. (Refer to 8.1 CHARACTERISTIC INSTRUCTIONS
OF µPD75236.)
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