Maxim Integrated MAX31782 - Manual (Page 170)

MaximIntegrated 19-5
MAX31782 User’s Guide
Revision 0; 8/11
High(16-bitdestination)←8-bitsource
To modify only the high byte of a given 16-bit destination, the 16-bit register should be moved into the GR register such
that the low byte can be singulated and the high byte can be written exclusively . Additional cycles are required if the
destination index is greater than 0Fh or if the source index is greater than 0Fh .
move GR, DP[0] ; move DP[0] to the GR register
move PFX[0], #20h ; get the high byte of DP[0] via GRH
move DP[0], GRL ; store the new DP[0] value
; 16-bit destination sub-index: dst=10h
; 8-bit source sub-index: src=11h
move PFX[1], #00h ;
move GR, dst ; read dst word to the GR register
move PFX[1], #00h
move PFX[4], src ; get the new src byte
move dst, GRL ; store the new dst value
If the high byte needs to be cleared to 00h, the operation can be shortened by transferring only the GRL byte to the
16-bit destination (example follows):
move GR, DP[0] ; move DP[0] to the GR register
move DP[0], GRL ; store the new DP[0] value, 00h used for high byte
19.4ReadingandWritingRegisterBits
The MOVE instruction can also be used to directly set or clear any one of the lowest 8 bits of a peripheral register in
module 0h-5h or a system register in module 8h . The set or clear operation will not affect the upper byte of a 16-bit
register that is the target of the set or clear operation . If a set or clear instruction is used on a destination register that
does not support this type of operation, the register high byte will be written with the prefix data and the low byte will
be written with the bit mask (i .e ., all 0s with a single 1 for the set bit operation or all ones with a single 0 for the clear
bit operation) .
Register bits can be set or cleared individually using the MOVE instruction as follows .
move IGE, #1 ; set IGE (Interrupt Global Enable) bit
move APC.6, #0 ; clear IDS bit (APC.6)
As with other instructions, prefixing is required to select destination registers beyond index 07h .
The MOVE instruction may also be used to transfer any one of the lowest 8 bits from a register source or any bit of the
active accumulator (Acc) to the Carry flag . There is no restriction on the source register module for the ‘MOVE C, src .
bit’ instruction .
move C, IIR.3 ; copy IIR.3 to Carry
move C, Acc.7 ; copy Acc.7 to Carry
Prefixing is required to select source registers beyond index 15h .