M16C28 Datasheet, PDF (253/423 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/28 Group (M16C/28, M16C/28B)
15. A/D Converter
15.1.6 Simultaneous Sample Sweep Mode
In simultaneous sample sweep mode, analog voltages applied to the selected pins are converted one-by-
one to a digital code. The input voltages of AN0 and AN1 are sampled simultaneously using two circuits
of sample and hold circuit. Table 15.8 shows the simultaneous sample sweep mode specifications. Fig-
ure 15.16 shows the operation example in simultaneous sample sweep mode. Figure 15.17 shows
ADCON0 to ADCON2 registers and Figure 15.18 shows ADTRGCON registers in simultaneous sample
sweep mode. Table 15.9 shows the trigger select bit setting in simultaneous sample sweep mode. In
simultaneous sample sweep mode, Timer B0 underflow can be selected as a trigger by combining soft-
___________
ware trigger, ADTRG trigger, Timer B2 underflow, Timer B2 interrupt generation frequency setting counter
underflow or A/D trigger mode of Timer B.
Table 15.8 Simultaneous Sample Sweep Mode Specifications
Item
Specification
Function
The SCAN1 to SCAN0 bits in the ADCON1 register and ADGSEL1 to
ADGSEL0 bits in the ADCON2 register select pins. Analog voltage applied
to the selected pins is converted one-by-one to a digital code. At this time,
the input voltage of AN0 and AN1 are sampled simultaneously.
A/D Conversion Start Condition When the TRG bit in the ADCON0 register is "0" (software trigger)
Set the ADST bit in the ADCON0 register to “1” (A/D conversion started)
When the TRG bit in the ADCON0 register is "1" (hardware trigger)
The trigger is selected by TRG1 and HPTRG0 bits (See Table 15.9)
The ADTRG pin input changes state from “H” to “L” after setting the ADST
bit to “1” (A/D conversion started)
Timer B0, B2 or Timer B2 interrupt generation frequency setting counter
underflow after setting the ADST bit to “1” (A/D conversion started)
A/D Conversion Stop Condition A/D conversion completed (If selecting software trigger, the ADST bit is
automatically set to "0" ).
Set the ADST bit to "0" (A/D conversion halted)
Interrupt Generation Timing A/D conversion completed
Analog Input Pin
Select from AN0 to AN1 (2 pins), AN0 to AN3 (4 pins),AN0 to AN5 (6 pins), or
AN0 to AN7 (8 pins) ⁽¹⁾
Readout of A/D conversion result Readout one of the AN0 to AN7 registers that corresponds to the selected pin
NOTES:
1. AN00 to AN07 and AN20 to AN27 can be used in the same way as AN0 to AN7. However, all input pins
need to belong to the same group.
•Example when selecting AN0 to AN3 to A/D pins for sweep (SCAN1 to SCAN0="012")
A/D conversion started
A/D pin input voltage
sampling
A/D pin conversion
AN0
AN1
AN2
AN3
AN4
AN5
AN6
AN7
A/D interrupt request generated
Figure 15.16 Operation Example in Simultaneous Sample Sweep Mode
Rev. 2.00 Jan. 31, 2007 ^{page 233} of 385
REJ09B0047-0200