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GR716-DS-UM, May 2019, Version 1.29
129
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GR716
16.5
AMBA interface
16.5.1 Overview
The LEON3 processor uses one AHB master interface for all data and instruction accesses. Instruc-
tions and data are fetched with single READ cycles. Store data is performed using single accesses or a
two-beat incremental burst in case of 64-bit store.
The HPROT signals of the AHB bus are driven to indicate if the accesses is instruction or data, and if
it is a user or supervisor access.
In case of atomic accesses, a locked access will be made on the AMBA bus to guarantee atomicity as
seen from other masters on the bus.
16.5.2 Error handling
An AHB ERROR response received while fetching instructions will normally cause an instruction
access exception (tt=0x1).
An AHB ERROR response while fetching data will normally trigger a data_access_exception trap
(tt=0x9).
Table 118.
HPROT values
Type of access User/Super
HPROT
Instruction
User
1100
Instruction
Super
1110
Data
User
1101
Data
Super
1111