R01UH0822EJ0100 Rev.1.00
Page 235 of 1041
Jul 31, 2019
RX13T Group
15. Buses
15.2.4
Internal Peripheral Buses
Connection of peripheral modules to the internal peripheral buses is as described in
.
Requests for bus mastership from the CPU (internal main bus 1) and other bus masters (internal main bus 2) are
arbitrated through internal peripheral buses 1 to 3 and 6.
The priority order of the two internal main buses can be set using the bus priority control register (BUSPRI). The priority
order can be set with the internal peripheral bus 1 priority control bits (BUSPRI.BPIB[1:0]), internal peripheral buses 2
and 3 priority control bits (BUSPRI.BPGB[1:0]), and internal peripheral bus 6 priority control bits (BUSPRI.BPFB[1:0])
for the corresponding internal peripheral buses. When the priority order is fixed, internal main bus 2 has priority over
internal main bus 1. When the priority order is toggled, a bus has a lower priority when the request of that bus is
accepted.
The order of accepting requests may change depending on the BUSPRI setting (see
Figure 15.2
Priority Order Between Internal Peripheral Bus Accesses
Table 15.4
Connection of Peripheral Modules to the Internal Peripheral Buses
Type of Bus
Peripheral Modules
Internal peripheral bus 1
DTC, interrupt controller, and bus error monitoring section
Internal peripheral bus 2
Peripheral modules other than those connected to internal peripheral buses 1 and 3
Internal peripheral bus 3
CMPC
Internal peripheral bus 6
ROM (P/E)/E2 DataFlash
Internal main bus 2
(R11)
R12
R24
R25
R21
Internal main bus 1
(R11)
R22
R23
(R11)
R11
>
>
Internal main bus 2
(R11)
R13
R25
R23
R24
R21
Internal main bus 1
R11
(R22)
R22
(R12)
>
>
>
>
R12
>
>
>
>
>
>
>
>
>
>
(R13) (R13)
R13
Request issued; not accepted
Request issued; accepted
No request issued
Priority order fixed:
Priority order toggled:
(1)
(2)
(*)
*
(1), (2) : The priority order does not change because the priority of the accepted request is low.