Stop/Slow Modes During Ad Conversion - Philips CEM2100/00 Service Manual

Example :After selecting the conversion time 19.5 µs at 16 MHz and the analog input channel AIN3 pin, perform AD con-
version once. After checking EOCF, read the converted value, store the lower 2 bits in address 0009EH nd store
the upper 8 bits in address 0009FH in RAM. The operation mode is software start mode.
SLOOP :

17.4 STOP/SLOW Modes during AD Conversion

When standby mode (STOP or SLOW mode) is entered forcibly during AD conversion, the AD convert operation
is suspended and the AD converter is initialized (ADCCR1 and ADCCR2 are initialized to initial value). Also, the
conversion result is indeterminate. (Conversion results up to the previous operation are cleared, so be sure to read
the conversion results before entering standby mode (STOP or SLOW mode).) When restored from standby mode
(STOP or SLOW mode), AD conversion is not automatically restarted, so it is necessary to restart AD conversion.
Note that since the analog reference voltage is automatically disconnected, there is no possibility of current flowing
into the analog reference voltage.
: (port setting) :
: :
LD (ADCCR1) , 00100011B
LD (ADCCR2) , 11011000B
SET (ADCCR1) . 7
TEST (ADCDR2) . 5
JRS T, SLOOP
LD A , (ADCDR2)
LD (9EH) , A
LD A , (ADCDR1)
LD (9FH), A
Page 217
T5CL8
;Set port register approrriately before setting AD
converter registers.
(Refer to section I/O port in details)
; Select AIN3
;Select conversion time(312/fc) and operation
mode
; ADRS = 1(AD conversion start)
; EOCF= 1 ?
; Read result data
; Read result data