ML620Q503/Q504 User's Manual
Chapter 24 RC Oscillation Type A/D Converter
FEUL620Q504 24-19
Figure 24-14 shows, as an example of method, a timing diagram of one cycle of conversion from analog value
RT0 to a digital value, that is, A/D conversion.
Basically, one A/D conversion cycle must consist of two steps, as shown in Figure 24-14. The reason for
requiring two steps is that the reference resistor and the thermistor must first be oscillated separately and then the
ratio between the oscillation frequencies of them is used, as described above.
In the example below, operation for these two steps is performed using the following combination:
•
First step = RC oscillation with RS0 in Counter A reference mode
•
Second step = RC oscillation with RT0 in Counter B reference mode
Besides this, there would be several possible A/D conversion methods.
In the above method, the operation time (gate time) for the second step fluctuates depending on the value of
thermistor RT0. To avoid the fluctuation of the operation time, using a method that uses the following
combination is recommended:
•
First step = RC oscillation with RS0 in Counter B reference mode
•
Second step = RC oscillation with RT0 in Counter A reference mode
A/D conversion procedure is explained below by taking Figure 24-14 as an example.
b
32.768kHz
reference clock
BSCLK
01H
RADMOD
(bit 4
~
0)
01H (ERAD=1)
RADCON
(bit0)
n
c
00H
r
00H
f
12H
CR oscillation
status
(
CROSC0
)
stop
stop
oscillating RS0
stop
oscillating RT0
(
Counter A reference mode
)
(
Counter B reference mode
)
0.366 sec
nA0
・
t
BSCLK
=nB0
・
t
RCCLK
(RS0)
nB0
・
t
RCCLK
(RT0)=nA1
・
t
BSCLK
(Up count by BSCLK)
Counter A
000000H
00000H
0
(Up count by BSCLK)
nA1
0FFFB50H
k
(Up count by RCCLK(RS0))
Counter B
000000H
000000H
l
nB0
(Up count by RCCLK(RT0))
1000000H-nB0
INT occurred
a
d
RC-ADC interrupt request
RADINT
e
s
o
HLT
Over flow
p
INT occurred
〈
1st step
〉
〈
2nd step
〉
Note
)
nA0=4B0H
,
t
BSCLK
=1/32768Hz
,
~
s
:
software
,
a
~
f
:
hardware
Overflow
00H
01H (ERAD=1)
Содержание LAPIS SEMICONDUCTOR ML620Q503
Страница 2: ...ML620Q503 Q504 User s Manual Issue Date Apr 16 2015 FEUL620Q504 01...
Страница 18: ...Chapter 1 Overview...
Страница 32: ...Chapter 2 CPU and Memory Space...
Страница 44: ...Chapter 3 Reset Function...
Страница 50: ...Chapter 4 Power Management...
Страница 70: ...Chapter 5 Interrupts...
Страница 134: ...Chapter 6 Clock Generation Circuit...
Страница 161: ...Chapter 7 Time Base Counter...
Страница 170: ...Chapter 8 Timers...
Страница 183: ...Chapter 9 Function Timer FTM...
Страница 231: ...Chapter 10 Watchdog Timer...
Страница 239: ...Chapter 11 Synchronous Serial Port SSIO...
Страница 251: ...Chapter 12 Synchronous Serial Port with FIFO SSIOF...
Страница 283: ...Chapter 13 UART...
Страница 303: ...Chapter 14 UART with FIFO UARTF...
Страница 327: ...Chapter 15 I2 C Bus Interface...
Страница 344: ...Chapter 16 Port XT...
Страница 350: ...Chapter 17 Port 0...
Страница 361: ...Chapter 18 Port 1...
Страница 368: ...Chapter 19 Port2...
Страница 379: ...Chapter 20 Port 3...
Страница 395: ...Chapter 21 Port 4...
Страница 410: ...Chapter 22 Port 5...
Страница 426: ...Chapter 23 Melody Driver...
Страница 439: ...Chapter 24 RC Oscillation type A D Converter RC ADC...
Страница 462: ...Chapter 25 Successive Approximation Type A D Converter SA ADC...
Страница 479: ...Chapter 26 Analog Comparator...
Страница 489: ...Chapter 27 Flash Memory Control...
Страница 505: ...Chapter 28 Voltage Level Supervisor VLS...
Страница 517: ...Chapter 29 LLD circuit...
Страница 519: ...Chapter 30 On Chip Debug Function...
Страница 522: ...Appendixes...
Страница 552: ...Revision History...