UPD784218 Datasheet, PDF (56/92 Pages) NEC – 16-/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784218, 784218Y
13. ROM CORRECTION
ROM correction is a function for avoiding execution of a part of a program in the internal ROM that needs to be
corrected by executing the corrected program, which is stored in the internal RAM.
By using this function, instruction bugs found in the internal ROM can be avoided and the program flow can be
changed.
Up to four combinations between source internal ROM (program) and target RAM sections are available for the
ROM correction.
Figure 13-1. ROM Correction Block Diagram
Program counter (PC)
Comparator
Coincidence
Correction address
pointer n
Correction branch processing
request signal
(CALLT instruction)
Correction address
register (CORAH, CORAL)
Remark n = 0 to 3, m = 0, 1
CORENn CORCHm
Internal bus
ROM correction control register
(CORC)
56
Data Sheet U12304EJ2V0DS00