Control Of Svd Circuit; Programming Notes - Epson S1C88650 Technical Manual

5.12.3 Control of SVD circuit

Table 5.12.3.1 shows the SVD circuit control bits.
Address Bit Name
00FF12 D7 –
D6 –
D5 SVDDT
D4 SVDON
D3 SVDS3
D2 SVDS2
D1 SVDS1
D0 SVDS0
SVDS3–SVDS0: 00FF12H•D3–D0
Criteria voltage for SVD is set as shown in Table
5.12.2.1.
At initial reset, this register is set to "0".
SVDON: 00FF12H•D4
Controls the SVD circuit ON and OFF.
When "1" is written: SVD circuit ON
When "0" is written: SVD circuit OFF
Reading:
When the SVDON register is set to "1", a supply
voltage detection is executed by the SVD circuit. As
soon as SVDON is reset to "0", the result is loaded
to the SVDDT latch. To obtain a stable detection
result, the SVD circuit must be ON for at least 500
µsec.
At initial reset, this register is set to "0".
SVDDT: 00FF12H•D5
This is the result of supply voltage detection.
When "0" is read:
When "1" is read:
Writing:
The result of supply voltage detection at time of
SVDON is set to "0" can be read from this latch.
At initial reset, SVDDT is set to "0".
S1C88650 TECHNICAL MANUAL
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (SVD Circuit)
Table 5.12.3.1 SVD circuit control bits
Function
–
–
SVD detection data
SVD circuit On/Off
SVD criteria voltage setting
SVDS3 SVDS2 SVDS1 SVDS0
1 1 1
1 1 1
1 1 0
: : :
0 0 1
Valid
Supply voltage (V –V
DD
Criteria voltage
Supply voltage (V –V
DD
< Criteria voltage
Invalid
1
–
–
Low
On
Voltage (V)
1 2.7
0 2.6
1 2.5
: :
1 1.8

5.12.4 Programming notes

(1) To obtain a stable detection result, the SVD
circuit must be ON for at least 500 µsec. So, to
obtain the SVD detection result, follow the
programming sequence below.
1. Set SVDON to "1"
2. Maintain for 500 µsec minimum
3. Set SVDON to "0"
4. Read SVDDT
(2) The SVD circuit should normally be turned OFF
because SVD operation increase current con-
sumption.
)
SS
)
SS
EPSON
0 SR R/W Comment
–
– Constantly "0" when
–
– being read
0 R
Normal
0 R/W
Off
0 R/W
0 R/W
0 R/W
0 R/W
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