285
Bit 7—Clock Select (CKS): Bits CKS and CKS1 select the A/D conversion speed.
Conversion Time
Bit 5: CKS1
Bit 7: CKS
Conversion Period
ø = 2 MHz
ø = 5 MHz
0
0
Reserved (initial value)
—
—
1
124/ø
62
µ
s
24.8
µ
s
1
0
62/ø
31
µ
s
12.4
µ
s
1
31/ø
15.5
µ
s
—
*
Note:
*
Operation is not guaranteed if the conversion time is less than 12.4
µ
s. Set the bits to get a
value of at least 12.4
µ
s.
Bit 6—External Trigger Select (TRGE): Bit 6 enables or disables the start of A/D conversion by
external trigger input.
Bit 6: TRGE
Description
0
Disables start of A/D conversion by external trigger
(initial value)
1
Enables start of A/D conversion by rising or falling edge of external trigger at
pin
ADTRG
*
Note:
*
The external trigger (
ADTRG
) edge is selected by bit IEG4 of the interrupt edge select
register (IEGR). See 3.3.2 for details.
Bit 5—Clock Select 1 (CKS1): Bits CKS and CKS1 select the A/D conversion speed. See bit 7,
clock select (CKS) for details.
Bit 4—Reserved Bit: Bit 4 is reserved; it is always read as 1, and cannot be modified.
Bits 3 to 0—Channel Select 3 to 0 (CH3 to CH0): Bits 3 to 0 select the analog input channel.
The channel selection should be made while bit ADSF is cleared to 0.
Bit 3:
CH3
Bit 2:
CH2
Bit 1:
CH1
Bit 0:
CH0
Analog Input Channel
0
0
*
*
No channel selected
(initial value)
1
*
*
Reserved
1
0
0
0
AN
4
1
AN
5
1
0
AN
6
1
AN
7
1
*
*
Reserved
Note:
*
Don’t care