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CHAPTER 10 DATA BUFFER (DBF)
The data buffer consists of four nibbles allocated in addresses 0CH to 0FH in BANK0.
The data buffer is used as a data storage area when data is transferred to/from the CPU peripheral circuit (address
register, serial interface, and timer) by the GET and PUT instructions. By using the MOVT DBF, and @AR instructions,
fixed data in program memory can be read into the data buffer.
10.1 DATA BUFFER CONFIGURATION
Figure 10-1 shows the allocation of the data buffer in data memory.
As shown in Figure 10-1, the data buffer is allocated in address locations 0CH to 0FH in BANK0 and consists of
a total of 16 bits (4
×
4 bits).
Figure 10-1. Allocation of the Data Buffer
0
1
2
3
4
5
6
7
0
BANK0
Column address
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
Data memory
Data buffer
(DBF)
System register (SYSREG)
Row address
Figure 10-2 shows the configuration of the data buffer. As shown in Figure 10-2, the data buffer is made up of
sixteen bits with its least significant bit in bit 0 of address 0FH and its most significant bit in bit 3 of address 0CH.
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