Epson S1C33L03 User Manual
IV ANALOG BLOCK: A/D CONVERTER
S1C33L03 FUNCTION PART
EPSON
B-IV-2-5
A-1
B-IV
A/D
Setting the sampling time
The A/D converter contains ST[1:0] (D[1:0]) / A/D sampling register (0x40245) that allows the analog-signal
input sampling time to be set in four steps (3, 5, 7, or 9 times the input clock period).
However, this register should be used as set by default (ST = "11"; x9 clock periods).
Control and Operation of A/D Conversion
Figure 2.2 shows the operation of the A/D converter.
ADE
Trigger
ADST
A/D operation
ADD
ADF
Conversion-result read
OWE
Interrupt request
AD0
AD0
Sampling
Conversion
AD1
AD1
Sampling
Conversion
AD2
AD0 converted data
AD1 converted data
(When AD0 to AD2 are converted)
AD2 converted data
ADD is overwritten
AD2
Sampling
Conversion
(1) Normal mode
ADE
Trigger
ADST
A/D operation
ADD
ADF
Conversion-result read
OWE
Interrupt request
AD0-1
AD0-1
Sampling
Conversion
AD0-2
AD0-2
Sampling
Conversion
AD0-3
AD0-1 converted data AD0-2 converted data
(When only AD0 is converted)
Reset in software
invalid
Sampling Conversion
(2) Continuous mode
Figure 2.2 Operation of A/D Converter
Starting up the A/D converter circuit
After the settings specified in the preceding section have been made, write "1" to ADE (D2) / A/D enable
register (0x40244) to enable the A/D converter. The A/D converter is thereby readied to accept a trigger to
start A/D conversion. To set the A/D converter again, or if it is not be used, set ADE to "0".
Starting A/D conversion
When a trigger is input while ADE = "1", A/D conversion is started. If a software trigger has been selected,
A/D conversion is started by writing "1" to ADST (D1) / A/D enable register (0x40244).
Only the trigger selected using TS[1:0] (D[4:3]) / A/D trigger register (0x40242) are valid; no other trigger is
accepted.