Rev. 1.0, 02/00, page 521 of 1141
24.2.4
A/D Control/Status Register (ADCSR)
0
—
—
0
1
0
R
2
0
R
3
0
4
0
R/W
5
0
6
7
R/(W)*
R
R/W
ADIE
0
R/(W)*
SEND
SST
HST
BUSY
SCNL
HEND
1
Bit :
Initial value :
R/W :
Note: * Only 0 can be written to bits 7 and 6, to clear the flag.
The A/D status register (ADCSR) is an 8-bit register that can be used to start or stop A/D
conversion, or check the status of the A/D converter.
A/D conversion starts when 1 is written in SST flag. A/D conversion can also start by setting HST
flag to 1 by hardware- or external-triggering.
For ADTRG start by HSW timing generator in hardware triggering, see section 26.4, HSW (Head-
switch) Timing Generator.
When conversion ends, the converted data is stored in the software-triggered A/D result register
(ADR) or hardware-triggered A/D result register (AHR), and the SST or HST bit is cleared to 0.
If software-triggering and hardware- or external-triggering are generated at the same time, priority
is given to hardware- or external-triggering.
ADCSR is an 8-bit register which is initialized to H'01 by a reset, and in module stop mode,
standby mode, watch mode, subactive mode and subsleep mode.
Bit 7
Software A/D End Flag (SEND): Indicates the end of A/D conversion.
Bit 7
SEND
Description
0
[Clearing Conditions]
(Initial value)
0 is written after reading 1
1
[Setting Conditions]
Software-triggered A/D conversion has ended
Bit 6
Hardware A/D End Flag (HEND): Indicates that hardware- or external-triggered A/D
conversion has ended.
Bit 6
HEND
Description
0
[Clearing Conditions]
(Initial value)
0 is written after reading 1
1
[Setting Conditions]
Hardware- or external-triggered A/D conversion has ended