R01UH0136EJ0210 Rev.2.10
Page 647 of 800
Jul 31, 2012
M16C/64A Group
27. A/D Converter
27.7.10 Repeat Mode, Repeat Sweep Mode 0, and Repeat Sweep Mode 1
In repeat mode, repeat sweep mode 0, and repeat sweep mode 1, when reading the ADi register (i = 0
to 7) during the period when the ADi register value is rewritten, an undefined value may be read. Read
the ADi register several times to determine whether the read value is valid. The period for reading an
undefined value is one cycle of fAD.
Figure 27.19 Period When the ADi Register Value is Rewritten
A/D conversion
AD0 register
AD1 register
AD7 register
One cycle of fAD
AN0
AN1
AN2
AN7
AN0
AN1
One cycle of fAD One cycle of fAD
One cycle of fAD
The AD0 register is rewritten during this period.
When reading the AD0 register during this period,
an undefined value is read.
The above diagram assumes the following:
•
Bits MD1 to MD0 in the ADCON0 register are 11b, and the MD2 bit in the ADCON1 register is 0
(repeat sweep mode 0).
•
Bits ADGSEL1 to ADGSEL0 in the ADCON2 register are 00b (AN0 to AN7 groups selected).
•
Bits SCAN1 to SCAN0 in the ADCON1 register are 11b (AN0 to AN7 (8 pins) selected).
Содержание M16C/60 Series
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