KS57C2308/P2308/C2316/P2316
ADDRESS SPACES
2-9
Working Register Banks
For addressing purposes, the working register area is divided into four register banks — bank 0, bank 1, bank 2,
and bank 3. Any one of these banks can be selected as the working register bank by the register bank selection
instruction (SRB n) and by setting the status of the register bank enable flag (ERB).
Generally, working register bank 0 is used for the main program, and banks 1, 2, and 3 for interrupt service
routines. Following this convention helps to prevent possible data corruption during program execution due to
contention in register bank addressing.
Table 2-3. Working Register Organization and Addressing
ERB Setting
SRB Settings
Selected Register Bank
3
2
1
0
0
0
0
–
–
Always set to bank 0
0
0
Bank 0
1
0
0
0
1
Bank 1
1
0
Bank 2
1
1
Bank 3
Paired Working Registers
Each of the register banks is subdivided into eight 4-bit registers. These registers, named Y, Z, W, X, H, L, E and
A, can either be manipulated individually using 4-bit instructions, or together as register pairs for 8-bit data
manipulation.
The names of the 8-bit register pairs in each register bank are EA, HL, WX, YZ and WL. Registers A, L, X and Z
always become the lower nibble when registers are addressed as 8-bit pairs. This makes a total of eight 4-bit
registers or four 8-bit double registers in each of the four working register banks.
Y
Z
W
X
H
L
E
A
(MSB)
(LSB)
(MSB)
(LSB)
Figure 2-5. Register Pair Configuration
Summary of Contents for KS57C2308
Page 30: ...ADDRESS SPACES KS57C2308 P2308 C2316 P2316 2 22 NOTES ...
Page 168: ...SAM47 INSTRUCTION SET KS57C2308 P2308 C2316 P2316 5 94 NOTES ...
Page 170: ......
Page 206: ...POWER DOWN KS57C2308 P2308 C2316 P2316 8 8 NOTES ...
Page 210: ...RESET KS57C2308 P2308 C2316 P2316 9 4 NOTES ...
Page 222: ...I O PORTS KS57C2308 P2308 C2316 P2316 10 12 NOTES ...
Page 272: ...LCD CONTROLLER DRIVER KS57C2308 P2308 C2316 P2316 12 24 NOTES ...
Page 280: ...SERIAL I O INTERFACE KS57C2308 P2308 C2316 P2316 13 8 NOTES ...
Page 294: ...MECHANICAL DATA KS57C2308 P2308 C2316 P2316 15 2 NOTES ...
Page 310: ...KS57P2308 P2316 OTP KS57C2308 P2308 C2316 P2316 16 16 NOTES ...
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