SH7708 datasheet(152/633 Pages) RENESAS

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7.3

UBC Operation

7.3.1

User Break Operation Flow

The flow from break condition setting to user break trap processing is as follows:

1. In the break conditions, set the break address in the break address register for the relevant

channel (BARA or BARB), the ASID corresponding to the break space in the break ASID

masking register (BAMRA or BAMRB). If the data bus value is included in the break

conditions, set the break data in the break data register (BDRB) and the data mask in the break

data mask register (BDMRB).

2. Set the break bus conditions in the break bus cycle register (BBRA or BBRB). If 00 is set for

even one set out of BBRA/BBRB register instruction fetch/data access select and read/write

select, a user trap break will not be generated in the corresponding channel.

Set such specifications as pre- or post-execution in the case of instruction fetch, whether the

data bus value is to be included in the conditions in the case of data access, and independent or

sequential conditions for channels A and B, in the break control register (BRCR).

Set the BBRA and BBRB registers only after all other break-related register settings have been

completed. If break enabling is set with the BBRA and BBRB registers while the break

address, data, mask, and other registers are still in their initial post-reset state, a break may

occur inadvertently.

3. When a condition is matched, the condition match flag for the relevant channel (CMFA or

CMFB) is set. This flag is set by a condition match but is not reset. To confirm setting of the

same flag again, therefore, it should first be cleared to 0.

4. When sequential conditions are set, a break is made at the instruction matched by channel B

when the channel B condition is matched after matching of the channel A condition. No break

is made if the channel B set condition is matched before or at the same time as the channel A

condition.

With sequential conditions, the condition match flag is set only for channel B, and not for

channel A.

SH7708 数据表(PDF) 152 Page - Renesas Technology Corp