Maxim-integrated MAX31782 Manual do Utilizador descarregar pdf (Página 168)

Maxim Integrated 19-3

MAX31782 User’s Guide

Revision 0; 8/11

does not require a prefixing operation even though the register DP[0] is 16-bit. This is because the prefix value defaults

to zero, so the line

move PFX[0],#00h

is not required.

19.3 Reading and Writing Registers

All functions in the MAX31782 are accessed through registers, either directly or indirectly. This section discusses load-

ing registers with immediate values and transferring values between registers of the same size and different sizes.

19.3.1 Loading an 8-Bit Register with an Immediate Value

Any writable 8-bit register with a sub-index from 0h to 7h within its module can be loaded with an immediate value in a

single cycle using the MOVE instruction.

move AP,#05h ;loadaccumulatorpointerregisterwith5hex

Writable 8-bit registers with sub-indexes 8h and higher can be loaded with an immediate value using MOVE as well,

but an additional cycle is required to set the prefix value for the destination.

move WDCN,#33h ;assemblesto: movePFX[2],#00h

    ;   move(WDCN-80h),#33h

19.3.2 Loading a 16-Bit Register with a 16-Bit Immediate Value

Any writable 16-bit register with a sub-index from 0h to 07h can be loaded with an immediate value in a single cycle if

the high byte of that immediate value is zero.

move LC[0],#0010h;prefixdefaultstozeroforhighbyte

If the high byte of that immediate value is not zero or if the 16-bit destination sub-index is greater than 7h, an extra cycle

is required to load the prefix value for the high byte and/or the high-order register index bits.

    ;highbyte<>#00h

move LC[0],#0110h;assemblesto: movePFX[0],#01h

    ;   moveLC[0],#10h

    ;destinationsub-index>7h

move A[8],#0034h;assemblesto: movePFX[2],#00h

    ;   move(A[8]-80h),#34h

19.3.3 Moving Values Between Registers of the Same Size

Moving data between same-size registers can be done in a single-cycle MOVE if the destination register’s index is from

0h to 7h and the source register index is between 0h and Fh.

move A[0],A[8] ;copyaccumulator8toaccumulator0

move LC[0],LC[1];copyloopcounter1toloopcounter0

If the destination register’s index is greater than 7h or if the source register index is greater than Fh, prefixing is required.

move A[15],A[0] ;assemblesto: movePFX[2],#00h

    ;   move(A[15]-80h),A[0]

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Maxim-integrated MAX31782 Manual do Utilizador Página 168