Atmel XMEGA B, User Manual

Page: 373 / 415

373 XMEGA B [DATASHEET]
8291B–AVR–01/2013
The REPEAT instruction cannot be repeated. The KEY instruction cannot be repeated, and will override the current value
of the repeat counter register.
29.4.6 Instruction Set Summary
The PDI instruction set summary is shown in Figure 29-10 on page 373 .
Figure 29-10.PDI instruction set summary.
29.5 Register Description - PDI Instruction and Addressing Registers
The PDI instruction and addressing registers are internal registers utilized for instruction decoding and PDIBUS
addressing. None of these registers are accessible as registers in a register space.
29.5.1 Instruction Register
When an instruction is successfully shifted into the physical layer shift register, it is copied into the instruction register.
The instruction is retained until another instruction is loaded. The reason for this is that the REPEAT command may force
the same instruction to be run repeatedly, requiring command decoding to be performed several times on the same
instruction.
0 0
LDS
0
Size A Size B Cmd
0 1 0
STS
1 0 0 LDCS
CS Address
1 1 0 STCS
1 1 0 0 0 KEY 1
1 0 0 0 0
REPEAT
1
Size B
LDS
STS
ST
0
1 0
0
0
1
1 1
LD
0
0
0
0
Cmd
LDCS (LDS Control/Status)
STCS (STS Control/Status)
KEY
1 0
0 1
1 1
REPEAT
1
1
1
1 0 0
Size B - Data size
Byte
3 Bytes
Long (4 Bytes)
0
1 0
0
0
1
1 1
Word (2 Bytes)
CS Address (CS - Control/Status reg.)
0 0 0 Register 0
Register 2
Reserved
Register 1
0
0 0 0 1
0 1 0 0
0 1 0 1
Reserved 1 1 1 1
......
0
0
Size A - Address size (direct access)
Byte
3 Bytes
Long (4 Bytes)
0
1 0
0
0
1
1 1
Word (2 Bytes)
0 0
LD
1
Ptr Size A/B Cmd
0 1 1
ST
0
0
0
0
Ptr - Pointer access (indirect access)
*(ptr)
ptr
ptr++ - Reserved
0
1 0
0
0
1
1 1
*(ptr++)
0 0