559CHAPTER 26 ROM CORRECTION26.1 ROM Correction FunctionsTheμPD78078, 78078Y Subseries can replace part of a program in the mask ROM with a program in the internalexpansion RAM.Instruction bugs found in the mask ROM can be avoided, and program flow can be changed by using the ROMcorrection.The ROM correction can correct two places (max.) of the internal ROM (program).Caution The ROM correction cannot be emulated by the in-circuit emulator (IE-78000-R, IE-78000-R-AIE-78001-R-A, IE-78K0-NS).26.2 ROM Correction ConfigurationThe ROM correction is executed by the following hardware.Table 26-1. ROM Correction ConfigurationItem ConfigurationRegister Correction address registers 0 and 1 (CORAD0, CORAD1)Control register Correction control register (CORCN)Figure 26-1 shows a block diagram of the ROM correction.Figure 26-1. Block Diagram of ROM CorrectionRemark n = 0, 1MatchCORENn CORSTnProgram counter (PC)ComparatorCorrection addressregister (CORADn)Internal busCorrection control registerCorrection branch requestsignal (BR !7FDH)
