SH7619_09 Datasheet, PDF (647/860 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7619 Series

Section 20 User Break Controller (UBC)
20.3.2 Break on Instruction Fetch Cycle
1. When L bus/instruction fetch/read/word or longword is set in the break bus cycle register
(BBRA/BBRB), the break condition becomes the L bus instruction fetch cycle. Whether it
breaks before or after the execution of the instruction can then be selected with the
PCBA/PCBB bit of the break control register (BRCR) for the appropriate channel. If an
instruction fetch cycle is set as a break condition, clear LSB in the break address register
(BARA/BARB) to 0. A break cannot be generated as long as this bit is set to 1.
2. If the condition is matched while a break before execution is selected, a break is generated
when it is confirmed that the instruction has been fetched and it will be executed. This means
this feature cannot be used on instructions fetched by overrun (instructions fetched at a branch
or during an interrupt transition, but not to be executed). When this kind of break is set in the
delay slot of a delayed branch instruction, the break is generated immediately before the
execution of the instruction that first accepts the break. Meanwhile, a break before the
execution of the instruction in a delay slot and a break after the execution of the SLEEP
instruction are also prohibited.
3. When a break after execution is selected, the instruction that matches the break condition is
executed and then the break is generated prior to the execution of the next instruction. As with
a break before execution, this cannot be used with overrun fetch instructions. When this kind
of break is set for a delayed branch instruction, a break is not generated until the first
instruction at which breaks are accepted.
4. When an instruction fetch cycle is set for channel B, the break data register B (BDRB) is
ignored. There is thus no need to set break data for the break of the instruction fetch cycle.
20.3.3 Break on Data Access Cycle
• The bus cycles in which L bus data access breaks occur are from instructions.
• The relationship between the data access cycle address and the comparison condition for each
operand size is listed in table 20.1.
Table 20.1 Data Access Cycle Addresses and Operand Size Comparison Conditions
Access Size
Longword
Word
Byte
Address Compared
Compares break address register bits 31 to 2 to address bus bits 31 to 2
Compares break address register bits 31 to 1 to address bus bits 31 to 1
Compares break address register bits 31 to 0 to address bus bits 31 to 0
Rev. 6.00 Jul. 15, 2009 Page 607 of 816
REJ09B0237-0600