M32C8A Datasheet, PDF (285/372 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M32C/80 Series

M32C/8A Group
18. A/D Converter
18.2 Functions
18.2.1 Resolution
The BITS bit in the AD0CON1 register determines the resolution. When the BITS bit is set to 1 (10-bit mode),
the A/D conversion result is stored into bits 9 to 0 in the AD0i register (i = 0 to 7). When the BITS bit is set to 0
(8-bit mode), the A/D conversion result is stored into bits 7 to 0 in the AD0i register.
18.2.2 Sample and Hold
When the SMP bit in the AD0CON2 register is set to 1 (with sample and hold), the A/D conversion rate per pin
increases to 28 φAD cycles for 8-bit resolution and 33 φAD cycles for 10-bit resolution. The sample and hold
function is available in all operating modes. Start A/D conversion after selecting whether the sample and hold
circuit is used or not.
18.2.3 Trigger Select Function
The TRG bit in the AD0CON0 register and the TRG0 bit in the AD0CON2 register determine a trigger to start
A/D conversion. Table 18.11 lists setting values for the trigger select function.
Table 18.11 Trigger Select Function Setting Values
Bit and Setting
AD0CON0 Register AD0CON2 Register
Trigger
TRG = 0
TRG = 1⁽¹⁾
−
TRG0 = 0
TRG0 = 1
Software trigger
A/D conversion starts when the ADST bit in the AD0CON0
register is set to 1
External trigger⁽²⁾
Falling edge of a signal applied to ADTRG
Hardware trigger⁽²⁾
Timer B2 interrupt request of three-phase motor control timer
function (after the ICTB2 register completes counting)
NOTES:
1. A/D conversion starts when the ADST bit is set to 1 (A/D conversion starts) and a trigger is generated.
2. A/D conversion starts over from the beginning, if an external trigger or a hardware trigger is inserted during
A/D conversion. (A/D conversion in progress is aborted.)
18.2.4 DMAC Operating Mode
DMAC operating mode is available in all operating modes. To select multi-port single sweep mode or multi-
port repeat sweep mode 0, DMAC operating mode must be used. When the DUS bit in the AD0CON3 register
is set to 1 (DMAC operating mode used), all A/D conversion results are stored into the AD00 register. DMAC
transfers the result from the AD00 register to a given memory space every time A/D conversion on a single pin
is completed. 8-bit DMA transfer must be selected for 8-bit resolution and 16-bit DMA transfer for 10-bit
resolution. Refer to 13. DMAC for DMAC instructions.
When using DMAC operating mode in single sweep mode, repeat sweep mode 0, repeat sweep mode 1, multi-
port single sweep mode, or multi-port repeat sweep mode 0, do not generate an external retrigger or hardware
retrigger.
18.2.5 Extended Analog Input Pins
In one-shot mode and repeat mode, the ANEX0 pin or ANEX1 pin can be used as the analog input pin. These
pins can be selected using bits OPA1 and OPA0 in the AD0CON1 register. The A/D conversion result for
ANEX0 input is stored into the AD00 register, and for ANEX1 input into the AD01 register. Both results are
stored into the AD00 register when the DUS bit in the AD0CON3 register is set to 1 (DMAC operating mode
used).
Set bits APS1 and APS0 in the AD0CON2 register to 00b (AN_0 to AN_7, ANEX0, ANEX1) and the MSS bit
in the AD0CON3 register to 0 (multi-port sweep mode not used).
Rev.1.00 Jul 15, 2007 Page 268 of 352
REJ09B0385-0100