117. SPM #2 – Store Program Memory
117.1. Description
SPM can be used to erase a page in the Program memory and to write a page in the Program memory
(that is already erased). An entire page can be programmed simultaneously after first filling a temporary
page buffer. The Program memory must be erased one page at a time. When erasing the Program
memory, the RAMPZ and Z-register are used as page address. When writing the Program memory, the
RAMPZ and Z-register are used as page or word address, and the R1:R0 register pair is used as data
(1)
.
Refer to the device documentation for detailed description of SPM usage. This instruction can address
the entire Program memory.
Note: 1. R1 determines the instruction high byte, and R0 determines the instruction low byte.
Operation:
(i) (RAMPZ:Z) ← $ffff Erase Program memory page
(ii) (RAMPZ:Z) ← R1:R0 Load Page Buffer
(iii) (RAMPZ:Z) ←
BUFFER
Write Page Buffer to Program memory
(iv) (RAMPZ:Z) ← $fff, Z
← Z + 2
Erase Program memory page, Z post
incremented
(v) BLBITS ← R1:R0, Z
← Z + 2
Load Page Buffer, Z post incremented
(vi) (RAMPZ:Z)
←BUFFER, Z ← Z +
2
Write Page Buffer to Program memory, Z
post incremented
Syntax: Operands: Program Counter:
(i)-(iii) SPM None PC ← PC + 1
(iv)-(vi) SPM Z+ None PC ← PC + 1
16-bit Opcode:
(i)-(iii) 1001 0101 1110 1000
(iv)-(vi) 1001 0101 1111 1000
117.2. Status Register (SREG) and Boolean Formula
I T H S V N Z C
– – – – – – – –
Words 1 (2 bytes)
Atmel AVR Instruction Set Manual [OTHER]
Atmel-0856L-AVR-Instruction-Set-Manual_Other-11/2016
171
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