Renesas 4513 Network Card User Manual


 
APPLICATION
2.5 A-D converter
2-51
4513/4514 Group User’s Manual
2.5.2 A-D converter application examples
(1) A-D conversion mode
Outline: Analog input signal from a sensor can be converted into digital values.
Specifications: Analog voltage values from a sensor is converted into digital values by using a 10-
bit successive comparison method. Use the AIN0 pin for this analog input.
Figure 2.5.2 shows the A-D conversion mode setting example.
Fig. 2.5.2 A-D conversion mode setting example
b3 b0
Disable Interrupts
A-D interrupt is temporarily disabled.
Interrupt enable flag INTE
Interrupt control register V2
“0”
All interrupts disabled (DI instruction)
A-D interrupt occurrence disabled
(TV2A instruction)
0
Set A-D Converter
A-D conversion mode is selected to A-D operation mode.
Analog input pin A
IN0
is selected.
A-D control register Q2
A-D conversion mode selected (TQ2A instruction)
A
IN0
selected (TQ1A instruction)A-D control register Q1
b3 b0
0
b3 b0
0
0
0
✕✕
Clear Interrupt Request
A-D interrupt activated condition is cleared.
A-D conversion completion flag ADF
“0”
A-D conversion interrupt activated condition cleared
(SNZAD instruction)
Note when the interrupt request is cleared
When is executed, considering the skip of the next instruction according to the
flag ADF, insert the NOP instruction after the SNZAD instruction.
When interrupt is
not used
When interrupt is used
Set Interrupt
Interrupts except A-D conversion is
enabled (EI instruction)
Set Interrupt
A-D conversion interrupt temporarily disabled is enabled.
b3 b0
1
✕✕
Interrupt control register V2
A-D interrupt occurrence enabled
(TV2A instruction)
Interrupt enable flag INTE
“1”
All interrupts enabled
(EI instruction)
Start A-D Conversion
A-D conversion operation is started (ADST instruction).
When interrupt is not used
When interrupt is used
Check A-D Interrupt Request
A-D conversion completion flag is
checked (SNZAD instruciton)
A-D Conversion Interrupt Occur
Execute A-D Conversion
High-order 8 bits of register AD register A and register B (TABAD instruction)
Low-order 2 bits of register AD high-order 2 bits of register A (TALA instruction)
“0” is set to low-order 2 bits of register A
”: it can be “0” or “1.”
When A-D conversion is executed by the same channel, to is repeated.
When A-D conversion is executed by the another channel, to is repeated.