A/D Control/Status Register (Adcsr) - Hitachi HD64465 User Manual

19.2.2

A/D Control/Status Register (ADCSR)

ADCSR is a 16-bit readable/writable register that selects the mode and controls the A/D converter.
ADCSR is initialized to H'0000 by a reset and is in STANDBY mode.
Bit 7
Bit Name ADF*
Initial Value 0
R/W R/W
*NOTE: Only 0 can be written to clear the flag bits.
Bit Description
7 A/D End Flag (ADF): Indicates the end of A/D conversion. When set to 1: In Single mode,
A/D conversion ends. In Scan mode, A/D conversion ends in all selected channels. When
set to 0: Cleared by reading ADF while ADF = 1, then writing 0 in ADF.
6 A/D Start (ADST): Starts or stops A/D conversion. The ADST bit value remains at 1
during A/D conversion. It can also be set to 1 by external trigger input at the ADTRG pin.
When set to 1: In Single mode, A/D conversion starts; ADST is automatically cleared to 0
when conversion ends. In Scan mode, A/D conversion starts and continues, cycling
among the selected channels, until ADST is cleared to 0 by software, or by a reset, or by
switching to STANDBY mode.
5 Interrupt Status (ADIS): Indicates the status of A/D interrupt request. When the bit is 1,
interrupt request is active. When the bit is 0, interrupt request is inactive. If software writes
0 to this bit, it can disable the interrupt request.
4 Trigger Enable (TRGE): Enables or disable external triggering of A/D conversion. When
set to 1, A/D conversion starts at the falling edge of the external trigger signal (ADTRG).
When set to 0, A/D conversion cannot be externally triggered.
3 A/D Interrupt Enable (ADIE): Enables or disables the interrupt (ADI) requested at the
end of an A/D conversion. When this bit is set to 1, A/D end interrupt request (ADI) is
enabled. When this bit is set to 0, A/D end interrupt request (ADI) is disabled.
2 Scan Mode (SCAN): Selects single mode or scan mode. For further information on the
operation of these modes, see section 19.3 Operation on page 331. Clear the ADST bit
to 0 before switching the conversion mode. When this bit is set to 1 is Scan mode. Set this
bit to 0 to enter Single mode.
1 - 0 Channel Select 1 and 0 (CH1 and CH0): These bits and the SCAN bit select the analog
input channels. Clear the ADST bit to 0 before changing the selected channel.
6 5 4
ADST ADIS* TRGE
0 0 0
R/W R/W R/W
3 2 1
ADIE SCAN CH1
0 0 0
R/W R/W R/W
Rev. 3.0, 03/01, page 337 of 390
0
CH0
0
R/W
Default
0
0
0
0
0
0
0