74. LDS – Load Direct from Data Space
74.1. Description
Loads one byte from the data space to a register. For parts with SRAM, the data space consists of the
Register File, I/O memory, and internal SRAM (and external SRAM if applicable). For parts without
SRAM, the data space consists of the register file only. The EEPROM has a separate address space.
A 16-bit address must be supplied. Memory access is limited to the current data segment of 64KB. The
LDS instruction uses the RAMPD Register to access memory above 64KB. To access another data
segment in devices with more than 64KB data space, the RAMPD in register in the I/O area has to be
changed.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i) Rd ← (k)
Syntax: Operands: Program Counter:
(i) LDS Rd,k 0 ≤ d ≤ 31, 0 ≤ k ≤ 65535 PC ← PC + 2
32-bit Opcode:
1001 000d dddd 0000
kkkk kkkk kkkk kkkk
74.2. Status Register (SREG) and Boolean Formula
I T H S V N Z C
– – – – – – – –
Example:
lds r2,$FF00 ; Load r2 with the contents of data space location $FF00
add r2,r1 ; add r1 to r2
sts $FF00,r2 ; Write back
Words 2 (4 bytes)
Cycles 2
Cycles XMEGA 2 If the LDS instruction is accessing internal SRAM, one extra cycle is inserted
Atmel AVR Instruction Set Manual [OTHER]
Atmel-0856L-AVR-Instruction-Set-Manual_Other-11/2016
116
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