SH7041A datasheet(586/923 Pages) RENESAS

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15.4

Operation

• The high speed A/D converter has 10-bit resolution.

• In addition to the four operating modes of select or group, and single or scan can be set in

combination with buffer operation and simultaneous sampling operation.

• Select mode uses one channel and group mode selects multiple channels.

• One start in the single mode performs conversions on all selected channels, and one start in the

scan mode performs repeated conversions until stopped by software.

• In buffer operation, the previous conversion result is saved in a buffer register at the end of a

conversion for the relevant channel.

• In simultaneous sampling operation, the analog input voltages of two channels are sampled

simultaneously then converted in order.

• Software, a timer conversion start trigger (MTU), or an ADTRG input can be selected as the

conversion start condition.

• High speed start mode or low power conversion mode can be selected for A/D conversion

using the PWR bit setting.

• When changing the operation mode or input channel, rewrite the ADCSR, ADCR while the

ADST bit is cleared to 0. After rewriting the ADCSR, ADCR, A/D conversion will be restarted

when the ADST bit is set to 1. Operation mode or input channel changes can be made

simultaneously with ADST bit setting. When stopping an A/D conversion before completion, 0

clear the ADST bit.

15.4.1

Select-Single Mode

Choose select-single mode when doing A/D conversions for one channel only.

When the ADST bit is set to 1, A/D conversion is started according to the designated conversion

start conditions. The ADST bit is held to 1 during the A/D conversion and is automatically cleared

to 0 upon completion.

The ADF flag is also set to 1 at the end of conversion. If the ADIE bit is set to 1 at this time, an

ADI interrupt request is generated. The ADF flag is cleared by reading the ADCSR, then writing a

Figure 15.4 shows an example of operation in the select-single mode when AN1 is selected.

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