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S3C9454B/F9454B
Smart Option
Smart option is the ROM option for starting condition of the chip.
The ROM addresses used by smart option are from 003CH to 003FH. The S3C9454B/F9454B only use 003EH,
003FH. Not used ROM address 003CH, 003DH should be initialized to be initialized to 00H. The default value of
ROM is FFH (LVR enable, internal RC oscillator).
NOTES:
1. When you use external oscillator, P1.0, P1.1 must be set to output
port to prevent current consumption.
2. The value of unused bits of 3EH, 3FH is don't care.
3. When LVR is enabled, LVR level must be set to appropriate value,
not default value.
ROM Address: 003CH
MSB
.7
.6
.5
Must be initialized to 00H.
ROM Address: 003DH
MSB
.7
.6
.5
Must be initialized to 00H.
ROM Address: 003EH
MSB
.7
.6
.5
LVR enable/disable bit:
0 = Disable
1 = Enable
LVR level selection bits:
11001 = 2.3 V
10010 = 3.0 V
01100 = 3.9 V
ROM Address: 003FH
MSB
.7
.6
.5
Not used.
Figure 2-2. Smart Option
.4
.3
.2
.1
.4
.3
.2
.1
.4
.3
.2
.1
Not used
.4
.3
.2
.1
Oscillator selection bits:
00 = External crystal/
ceramic oscillator
01 = External RC
10 = Internal RC (0.5 MHz in V
11 = Internal RC (3.2 MHz in V
ADDRESS SPACES
.0
LSB
.0
LSB
.0
LSB
.0
LSB
DD
DD
= 5 V)
= 5 V)
2-3
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