Rev. 1.10
50
October 23, 2020
Rev. 1.10
51
October 23, 2020
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
Example 2
data .section ´data´
adres1 db ?
adres2 db ?
adres3 db ?
adres4 db ?
block db ?
code .section at 0 ´code´
org 00h
start:
mov
a,
04h
;
setup
size
of
block
mov block, a
mov
a,
01h
;
setup
the
memory
sector
mov mp1h, a
mov a, offset adres1 ; Accumulator loaded with first RAM address
mov mp1l, a ; setup memory pointer with first RAM address
loop:
clr IAR1 ; clear the data at address defined by MP1
L
inc mp1l ; increment memory pointer MP1L
sdz block ; check if last memory location has been
;
cleared
jmp loop
continue:
The important point to note here is that in the example shown above, no reference is made to specific
Data Memory addresses.
Direct Addressing Program Example using extended instructions
data .section ´data´
temp db ?
code .section at 0 ´code´
org 00h
start:
lmov
a,
[m]
;
move
[m]
data
to
acc
lsub a, [m+1] ; compare [m] and [m+1] data
snz
c ;
[m]>[m+1]?
jmp
continue
;
no
lmov a, [m] ; yes, exchange [m] and [m+1] data
mov temp, a
lmov a, [m+1]
lmov [m], a
mov a, temp
lmov [m+1], a
continue:
Note: Here “m” is a data memory address located in any data memory sectors. For example,
m=1F0H, it indicates address 0F0H in Sector 1.
Accumulator – ACC
The Accumulator is central to the operation of any microcontroller and is closely related with
operations carried out by the ALU. The Accumulator is the place where all intermediate results
from the ALU are stored. Without the Accumulator it would be necessary to write the result of
each calculation or logical operation such as addition, subtraction, shift, etc., to the Data Memory
resulting in higher programming and timing overheads. Data transfer operations usually involve
the temporary storage function of the Accumulator; for example, when transferring data between
one user-defined register and another, it is necessary to do this by passing the data through the
Accumulator as no direct transfer between two registers is permitted.
