ST20CX View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST20CX

Instruction Set Reference Manual

STMicroelectronics 

devsb

devsb

device store byte

Code: 2F F1

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

peripheral. Store the least significant byte of Breg into the byte addressed by Areg.

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 store instructions that appear

before it in the code sequence, and before all normal memory stores that appear after

it.

Definition:

if (PeripheralStart ≤ Areg ≤ PeripheralEnd)

PeripheralByte′[Areg] ← Breg0..7

else

byte′[Areg] ← Breg0..7

Areg′ ← Creg

Breg′ ← undefined

Creg′ ← undefined

Error signals: none

Comments:

Secondary instruction.

See also: devlb devss devsw sb

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