426
8331B–AVR–03/12
Atmel AVR XMEGA AU
address - and data access. Four different address/data sizes are supported; byte, word, 3 bytes,
and long (4 bytes). Multiple-bytes access is internally broken down to repeated single-byte
accesses, but it reduces the protocol overhead.
32.5.6.5
LDCS - Load Data from PDI Control and Status Register Space
The LDCS instruction is used to load data from the PDI control and status registers into the
physical layer shift register for serial read out. The LDCS instruction supports only direct
addressing and single-byte access.
32.5.6.6
STCS - Store Data to PDI Control and Status Register Space
The STCS instruction is used to store data that are serially shifted into the physical layer shift
register to locations within the PDI control and status registers. The STCS instruction supports
only direct addressing and single-byte access.
32.5.6.7
KEY - Set Activation Key
The KEY instruction is used to communicate the activation key bytes required for activating the
NVM interfaces.
32.5.6.8
REPEAT - Set Instruction Repeat Counter
The REPEAT instruction is used to store count values that are serially shifted into the physical
layer shift register to the repeat counter register. The instruction that is loaded directly after the
REPEAT instruction operand(s) will be repeated a number of times according to the specified
repeat counter register value. Hence, the initial repeat counter value plus one gives the total
number of times the instruction will be executed. Setting the repeat counter register to zero
makes the following instruction run once without being repeated.
The REPEAT instruction cannot be repeated. The KEY instruction cannot be repeated, and will
override the current value of the repeat counter register.
32.5.7
Instruction Set Summary
The PDI instruction set summary is shown in
.
