SuperH (SH) 64-bit RISC Series SH-5 System Architecture, Volume ...

PRELIMINARY DATA
DBUS protocol 227
Request message originated by external agent
Bit 0
Bit N
Opcode (opc, r_opc)
Opcode is a 1-byte field which defines the contents of the message.
Address (addr)
For request messages originated by the CPU or other SuperHyway module
addressed to the SHdebug link portion of the debug module address space (that is,
the remote memory area which is hosted on the development host or debug adaptor),
the top 8-bits of the address field contain the SuperHyway device code for the debug
module.
For request messages originated by the development host or debug adapter, the top
8-bits of the address field identifies the destination SuperHyway device. The top 8
bits of the address must not be the value associated with the remote memory area.
The SH-5 behavior is undefined if such an access is attempted.
Source (src, r_src)
opc addr src tid
msk/data pairs
1 byte 4 bytes 1 byte 1 byte
0 - 36 bytes
Response message from SH-5
Bit 0
Message
Type field
+ dummy
1 byte
r_opc
1 byte
r_src
1 byte
r_tid
1 byte
r_data
0 - 32 bytes
Figure 17: DBUS transaction originated by external agent
D R A FT
This field identifies the source of the request. When generating a response, the tool
must ensure that the value in the source field matches the Source field of the
original request.
Bit N
05-SA-10003 v1.0
SuperH, Inc.
SH-5 System Architecture, Volume 3: Debug