110
EPSON
S1C63808 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (SVD Circuit)
4.13.3 I/O memory of SVD circuit
Table 4.13.3.1 shows the I/O addresses and the control bits for the SVD circuit.
Table 4.13.3.1 Control bits of SVD circuit
Address
Comment
D3
D2
Register
D1
D0
Name
Init 1
10
FF05H
00
SVDDT SVDON
RR/W
0 3
SVDDT
SVDON
– 2
0
Low
On
Normal
Off
Unused
SVD evaluation data
SVD circuit On/Off
FF04H
SVDCHG SVDS2 SVDS1 SVDS0
R/W
SVDCHG
SVDS2
SVDS1
SVDS0
0
3.0 V
1.5 V
SVD voltage system selection
SVD criteria voltage setting
1
1.10
1.80
2
1.15
1.90
3
1.20
2.00
4
1.25
2.10
5
1.30
2.40
6
1.40
2.70
7
1.50
2.90
[SVDS2–0]
1.5 V (V)
3.0 V (V)
0
1.05
1.70
*1 Initial value at initial reset
*2 Not set in the circuit
*3 Constantly "0" when being read
SVDCHG: SVD voltage set selection register (FF04HD3)
Selects an SVD criteria voltage combination according to the supply voltage.
When "1" is written: 3.0 V (typ.)
When "0" is written: 1.5 V (typ.)
Reading: Valid
When SVDCHG is set to "1", the 8-level criteria voltage set is configured for a 3.0 V supply voltage and
when it is set to "0", voltages are configured for a 1.5 V supply voltage.
At initial reset, this register is set to "0".
SVDS2–SVDS0: SVD criteria voltage setting registers (FF04HD2–D0)
Criteria voltage for SVD is set as shown in Table 4.13.2.1.
At initial reset, these registers are set to "0".
SVDON: SVD control (on/off) register (FF05HD0)
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 1 msec.
At initial reset, this register is set to "0".
SVDDT: SVD data (FF05HD1)
This is the result of supply voltage detection.
When "0" is read: Supply voltage (VDD–VSS)
≥ Criteria voltage
When "1" is read: Supply voltage (VDD–VSS) < Criteria voltage
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".