RX610 Group
11. Buses
R01UH0032EJ0120 Rev.1.20
Page 299 of 1006
Feb 20, 2013
11.6
Bus Error Monitoring Section
The bus-error monitoring section monitors the individual areas for bus errors, and generates an interrupt when it detects a
bus error.
11.6.1
Types of Bus Error
There are two types of bus error: illegal address access and time-out.
Illegal address access is the detection of illegal access to an area, and time-out is the detection of a bus-access operation
not being completed within 768 cycles.
11.6.1.1
Illegal Address Access
When the illegal address access detection enable bit in the bus-error enable register is set (BEREN.IGAEN = 1), access
of the following types leads to illegal address access errors.
•
Access to areas of external address space for which operation has been disabled (CSiCNT.EXENB = 0; i = 0 to 7)
•
Access to illegal address ranges other than in areas for which operation has been disabled
The address ranges where access will lead to illegal address access errors are indicated in table 11.10.
11.6.1.2
Time-out
When the time-out detection enable bit in the bus-error enable register is set (BEREN.TOEN = 1), bus access that is not
completed within 768 cycles leads to a time-out error. Cycles of the operating clock of the relevant slave are counted as
the number of cycles.
•
External address space: Once a bus-access operation has started, access is not completed (the WAIT# signal is not
negated) within 768 cycles.
Note: In products of the RX610 Group, time-out errors are only generated for access to external address space.
11.6.2
Operations When a Bus Error Occurs
Generation of an interrupt (BUSERR) can be selected by setting the bus error notification bit (BERIE.CPEN = 1).