A-D CONVERTER
[Precautions for A-D converter]
[Precautions for A-D converter]
1. Be sure to clear the VREF connection select bit to “0.”
2. Writing to the following must be performed before a trigger is generated (in other words, while the A-D
converter halts); this must be done independent of the operation mode of the A-D converter.
• Each bit of the A-D control register 0, except bit 6
• Each bit of the A-D control register 1
• A-D register i (when the comparator function is selected)
• Comparator function select register 0
• Comparator result register 0
Especially, when any instruction which clears the VREF connection select bit from “1” to “0” has been
executed (in other words, the resistor ladder network is connected with pin VREF by this instruction), an
interval of 1 µs or more must be elapsed before occurrence of a trigger.
3. Reading from A-D register i (when the comparator function is selected) must be performed before occurrence
of a trigger (in other words, while the A-D converter halts.). The value undefined at reading.
4. When using pin AN
When using pin AN
3
4
, be sure that the D-A
, be sure that the D-A
0
1
output enable bit (bit 0 at address 9616) = “0” (output disabled).
output enable bit (bit 1 at address 9616) = “0” (output disabled).
5. Note that the operation time for pins AN
0
to AN
4
is equivalent to the time for 6 pins when the A-D sweep
pin select bits (bits 1, 0 at address 1F16) = “10
2
” in the single sweep mode and repeat sweep mode 0.
6. Refer to section “Appendix. 7 Countermeasures against noise” when using the A-D converter.
7906 Group User’s Manual Rev.2.0
12-31
RENESAS [ RENESAS TECHNOLOGY CORP ]
