SD6830P AUK [AUK corp], SD6830P Datasheet - Page 7

• Manufacturer Part Number: SD6830P
• Description: 4BIT MICROCONTROLLER
• Manufacturer: AUK [AUK corp]

6.3 Data Memory (RAM)
Data memory is used to store various type of processing data. This consists of a 32-nibble,
which is organized into two files of 16 nibbles each. RAM addressing is indirectly
implemented by a two registers; H, L. It’s upper 1-bit register (H) selects one of two files
and its lower 4-bit register (L) selects one of 16 nibbles in the selected file.
Stack register is used to store return address and provide a particularly mechanism for
transferring control between programs. Two level hardware push/pop stacks are
manipulated by CAL, CALL, and RET instructions. CAL/CALL instructions push the current
program counter value, incremented by “1”, into stack level 1. Stack level 1 is
automatically pushed to level 2.
If more than two subsequent CAL/CALL are executed, only the most recent two return
addresses are stored. RET instruction load the contents of stack level 1 into the program
counter while stack level 2 gets copied into level 1. If more than two subsequent RET are
executed, the stack will be filled with the address previously stored in level 2.
6.4 Stack Register (SK)
12
0
13
1
FILE 0
14
DATA MEMORY
2
REG H (1-bit)
12
0
15
3
Figure 6-2. Data Memory Map
13
1
FILE 1
KSI-W002-000
14
2
15
3
REG L ( 4-bit )
4
Lower
3-bit
PORT
F
SD6830
F0
F1
F2
F3
F4
F5
F6
F7
7