UPD78F0890GK(A)-GAJ-AX NEC, UPD78F0890GK(A)-GAJ-AX Datasheet - Page 89

• Manufacturer Part Number: UPD78F0890GK(A)-GAJ-AX
• Description: 8BIT MCU, 128K FLASH, 7K RAM, LQFP
• Manufacturer: NEC

Specifications of UPD78F0890GK(A)-GAJ-AX

• Controller Family/series: UPD78F
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 10
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

4.4.4 Instruction branch to bank area by interrupt
vector table, but it is difficult to identify the BANK register when the interrupt occurs.
7FFFH), specify the memory bank at the branch destination by using the BANK register in the common area, and
execute the CALL instruction. At this time, save the BANK register value before the change to RAM, and restore the
value of the BANK register before executing the RETI instruction.
When an interrupt occurs, instructions can branch to the memory bank specified by the BANK register by using the
Therefore, specify the branch destination address specified by the vector table in the common area (0000H to
• Software example (when using interrupt request of 16-bit timer/event counter 00)
VCTBL
RAMD
R_BNKRN: DS
BNKC
BNKITM000:
BN3
TEST:
END
Remark Allocate interrupt servicing that requires a quick response in the common area.
CSEG
DW
DSEG
CSEG
PUSH
MOV
MOV
MOV
CALL
MOV
MOV
POP
RETI
CSEG
MOV ⋅⋅⋅
RET
Common
area
Bank
area
:
:
CHAPTER 4 MEMORY BANK SELECT FUNCTION (
AT
BNKITM000
SADDR
AT
AX
A,BANK
R_BNKRN,A
BANK,#BANKNUM TEST
!TEST
A,R_BNKRN
BANK,A
AX
BANK3
1
0020H
7000H
Memory bank m
Vector table
User’s Manual U17554EJ4V0UD
; Specifies an address at the timer interrupt destination.
; Secures RAM for saving the memory bank number before the interrupt occurs.
; Inter-memory bank interrupt servicing routine
; Saves the contents of the AX register.
; Calls the interrupt routine.
; Restores the memory bank number before the interrupt.
; Restores the contents of the AX register.
; Interrupt servicing routine
; Saves the memory bank number before the interrupt to RAM.
; Specifies the memory bank number of the interrupt routine.
Instruction branch
Save the original memory bank number.
Specify the address and memory bank
at the destination, and execute the call
instruction.
PD78F0889, 78F0890 ONLY)
Memory bank n
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