ST20CX View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST20CX

Instruction Set Reference Manual

STMicroelectronics 

devlb

devlb

device load byte

Code: 2F F0

Description: Perform a device read from memory, a memory-mapped device or a

peripheral. The byte addressed by Areg is read into Areg as an unsigned value. The

memory access performed by this instruction is guaranteed to be correctly sequenced

with respect to other device-access instructions. Also the instruction is guaranteed to

be executed after all normal memory load instructions that appear before it in the code

sequence, and before all normal memory loads that appear later.

Definition:

if (PeripheralStart ≤ Areg ≤ PeripheralEnd)

Areg′0..7 ← PeripheralByte[Areg]

else

Areg′0..7 ← byte[Areg]

Areg′8..31

←0

Error signals: none

Comments:

Secondary instruction.

See also: devls devlw devsb lb

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