I/O Memory Of Svd Circuit - Epson S1C63666 Technical Manual

CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (SVD Circuit)

4.17.4 I/O memory of SVD circuit

Table 4.17.4.1 shows the I/O addresses and the control bits for the SVD circuit.
Register
Address
D3 D2
0 SVDS2 SVDS1 SVDS0
FF04H
R
CMPON CMPDT SVDDT SVDON
FF05H
R/W R
*1 Initial value at initial reset
*2 Not set in the circuit
*3 Constantly "0" when being read
SVDS2–SVDS0: SVD criteria voltage setting register (FF04H•D2–D0)
Criteria voltage for SVD is set as shown in Table 4.17.3.1.
At initial reset, this register is set to "0".
SVDON: SVD control (on/off) register (FF05H•D0)
Turns the SVD circuit on and off.
When "1" is written: SVD circuit ON
When "0" is written: SVD circuit OFF
Reading: Valid
When SVDON is set to "1", a source 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: SVD data (FF05H•D1)
This is the result of supply voltage detection.
When "0" is read: Supply voltage (V
When "1" is read: Supply voltage (V
Writing: Invalid
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".
4.17.5 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 consumption.
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Table 4.17.4.1 Control bits of SVD circuit
∗1
D1 D0 Name Init
∗3 ∗2
0 –
SVDS2 0
SVDS1 0
R/W
SVDS0 0
CMPON 0
CMPDT 0
SVDDT 0
R/W
SVDON 0
DD
DD
1 0
Unused
SVD criteria voltage setting
[SVDS2–0]
Voltage(V) 1.85/0.98
On Off
Analog comparator On/Off
+ > - + < - Analog comparator data
Low Normal
SVD evaluation data
On Off SVD circuit On/Off
) ≥ Criteria voltage
–V
SS
–V ) < Criteria voltage
SS
EPSON
Comment
0 1 2 3 4
2.00 2.15 2.30 2.45 2.60
S1C63666 TECHNICAL MANUAL
5 6 7
2.75 2.90