SX8801IRXXMLTRT View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX8801IRXXMLTRT' PDF : 135 Pages View PDF
XE8801A – SX8801R
if x is odd, PBOut[x, x-1]
PBPullup[x]
PB[x] selection on
00
1
analog line 0
01
1
analog line 1
10
1
analog line 2
11
1
analog line 3
XX
0
High impedance
Table 12-8: Selection of the analog lines for PB[x] when x is odd and PBAna[x] = 1
if x is even, PBDir[x+1, x]
00
01
10
11
XX
PBPullup[x]
1
1
1
1
0
PB[x] selection on
analog line 0
analog line 1
analog line 2
analog line 3
High impedance
Table 12-9: Selection of the analog lines for PB[x] when x is even and PBAna[x] = 1
Example:
Set the pads PB[2] and PB[3] on the analog line 3. (the values X depend on the configuration of others
pads)
- apply high impedance in the analog mode (move RegPBPullup,#0bXXXX00XX)
- go to analog mode (move RegPBAna,#0bXXXXXX1X)
- select the analog line3 (move RegPBDir,#0bXXXX11XX and move RegPBOut,#0bXXXX11XX)
- connect the analog line to the pins (move RegPBPullup,#0bXXXX11XX)
12.5.2 Port B analog function specification
The table below defines the on-resistance of the switches between the pin and the analog bus for different
conditions. The series resistance between 2 pins of Port B connected to the same analog line is twice the
resistance given in the table.
sym
Ron
Ron
Cin
Cin
description
switch resistance
switch resistance
input capacitance (off)
input capacitance (on)
min
typ
max unit
Comments
11
kΩ
Note 1
15
kΩ
Note 2
3.5
pF
Note 3
4.5
pF
Note 4
Table 12-10. Analog input specifications.
Note 1: This is the series resistance between the pad and the analog line in 2 cases
1. VBAT ≥ 2.4V and the VMULT peripheral is present on the circuit and enabled.
2. VBAT ≥ 3.0V and the VMULT peripheral is not present on the circuit.
Note 2: This is the series resistance in case VBAT ≥ 2.8V and the peripheral VMULT is not present on the circuit.
Note 3: This is the input capacitance seen on the pin when the pin is not connected to an analog line. This value is
indicative only since it is product and package dependent.
Note 4: This is the input capacitance seen on the pin when the pin is connected to an analog line and no other pin
is connected to the same analog line. This value is indicative only since it is product and package dependent.
© Semtech 2005
12-4
www.semtech.com
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