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AURIX™ MCU: How to get the best performance from the SDMMC module – KBA237887

AURIX™ MCU: How to get the best performance from the SDMMC module – KBA237887

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Community Translated: AURIX™ MCU: SDMMCモジュールから最高のパフォーマンスを引き出す方法 - KBA237887

How do I get the best read and write performance from the SDMMC (SD- or eMMC Interface) with TC3xx?

To get the best possible read and write performance, use multi-block command operations with large files.

Make sure to use a file system that supports multi-block operations.

Use the host’s integrated DMA engine to optimize transfers depending on the size:

  • Single operation DMA (SDMA) short data transfer: only a single SD command transaction can be executed for each SDMA operation
  • Advanced DMA-2 (ADMA2) – lengthy data transfers: high transfer speed is obtained by using the scatter-gather DMA algorithm
  • Advanced DMA-3 (ADMA3) – very lengthy data transfers: execute multiple ADMA2 data transfers without the intervention of the host driver

Figure 1 SDMMC host simplified block diagram

For more details, refer to the feature list in the section “SD- and eMMC Interface (SDMMC)” from TC3xx User Manual Part 2.

Note: The bandwidth can be up to 400 Mbits/s for eMMC and up to 200 Mbits/s for SD cards, but the achieved read/write performance may differ depending on the memory device timings.

Note: This KBA applies to the following series:

  • AURIX™ TC3xx series