Posted by Govardhan Shanmuga Sundaram, April 9, 2018
Distinct Features of i.MX 7 from i.MX 6
Is i.MX 7 is an advanced and powerful successor of i.MX 6? We will ordinarily assume it that way, but the nuances of i.MX 7 shows that it is designed entirely for a different target segment. This is more specifically designed for the products that require low power, high battery life and low-moderate processing power.
Key features of i.MX7:
- Utilizes one or two Cortex A7 core paired with cortex M4 MCU
- Cortex M4 saves power by turning off A7
- Single core version of i.MX 7 will have 800 MHz Cortex A7 while the dual core will have peak clock frequency of 1 GHz
- Low Power State Retention (LPSR) mode" that is said to consume only 250 μW
While evaluating SDCAC in the host test platform i.MX 7, it throws an error "mmc0: Timeout waiting for hardware interrupt". The SDMAC driver could be successfully loaded, whereas initiating a connection request to connect SDCAC caused this error. SDCAC requires a 3.3V power supply to operate which is not supported by i.MX 7. This discrepancy is however managed by using external power supply to the SDCAC wireless module.
After initiating a connection request, the power monitor showed a sudden increase in current consumption. By design, i.MX7 SABRE SDB appeared inproficient of providing the sudden current demand. The schematic of the i.MX7 SABRE SDB shows that MEM_3V3 supplies a maximum of 1 A to the SD1 card slot.
We have investigated this issue further to help our customers understand why SDCAC is not compatable to evaluate in i.MX 7 platform, and developed an application note. This has the findings from the investigation for our customers. Please download the full application note for more information.