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Chapter 29 MPU / EDSU
3.Break Functions
In Operand address break mode the Operand Address, causing the break is captured in the BOAC register. Addi-
tional BIAC holds the instruction address of the instruction, which was executed one cycle before the break causing
data operation. This is normally the instruction, which has caused the data transfer.
In the operand address break mode the following important points have to be considered:
1) In the FR family architecture, if data access is performed with misalignment, the lower address bit 0 will be ig-
nored for halfword and the lower address bits 0 and 1 for word access. The mask register could be programmed
accordingly.
2) The EDSU operand break does not always occur immediately after completion of execution of the instruction
causing the break event.
3) Please see also information at chapter 3.4 Using operand with data break
3.3 Data value break
The data value break causes a break if specified data is read or written at a data access to an address specified by
the CPU. The data can be specified by the the data value break registers BAD0 and BAD1. Setting the CTC[1:0]
bits of the control register BCR0 to ’11’ provides this mode. The bits EP0 and EP1 in BCR0 enable the break con-
dition.
Up to 2 break points from channels 0 to 1 can be set. All data value break events are ORed into a operand break
exception to the CPU.
1 mask register (BAD0) is available for masking the data value (stored in BAD1) and 1 mask register (BAD2) is avail-
able for masking the operand address (BAD3) which is being accessed. Mask registers BAD2 and BAD0 can be
enabled with EM1 and EM0.
The data on which a break should be executed must be masked by a data-mask on the bus, requiring 32-bit setting
considering the address and data length (see table below). This is required due to the byte position of the operand
is dependent from the operand address. The setting of data length of the control register BCR0 OBS[1:0] could be
configured to all ignored. The data length is controllable by mask setting to the BAD0 register implicitely.
On break at BAD[1:0] the respective flags BD[1:0] in the break interrupt request register BIRQ will be set to ’1’. They
have to be reset by software in the operand break exception routine.
In Operand data value break mode the Operand Address, causing the break is captured in the BOAC register. Ad-
ditional BIAC holds the instruction address of the instruction, which was executed one cycle before the break caus-
ing data operation. This is normally the instruction, which has caused the data transfer.
In the data value break mode the following important points have to be considered:
1) The data value break is also executed for matching DMA transfers. This could lead to unexpected behaviour due
to parallel processes. The filter bits FDMA and FCPU could be set for dedicated investigations.
32 bit
4n + 0 Hit Hit Hit Hit
4n + 1 Hit Hit Hit Hit
4n + 2 Hit Hit Hit Hit
4n + 3 Hit Hit Hit Hit
Table 3-3 Operand size and operand address relations
Access data
length
Access
address
Address set in BOA0, BOA1
4n + 0 4n + 1 4n + 2 4n + 3