SJA1110 SPI_AP interface

[yangjinzhuang]

Hello,

       I see that SJA1110 supports SPI_HOST and SPI_AP access point in the UM11107 software UM for SJA1110.

       My hardware is GLDBOX, it's design is S32G274A---SPI---SJA1110

       I am not sure if I want to use SPI_AP interface, first I select the Pins SPI_HAP_SSx_N to SPI_HAP_SS0; second if I should connect the external controller's SPI_PER to sja1110's SPI_HAP?

       If I use SPI_AP, does SJA1110 can't boot and download image itself? so the external controller must be another SJA1110 and can't be S32J274A, even they have SPI connect? Is my understand right?

       Thank you very much!

[PavelL]

Hello @yangjinzhuang ,

SJA1110 supports NVM boot from external SPI flash or SDL boot from the host controller,  independently to usage of SPI_AP. Set DIP switch on your board accordingly to AN13185 chapter 3.2.1. You may also refer to UM11107 Software user manual for SJA1110 for more details. Both documents require Sign in.

You need to use SPI_HAP_SS0_N to access all internal registers/settings by SPI_AP.

SJA1110's SPI_PER is mostly used for cascading two SJA1110s.

Best regards,

Pavel

[yangjinzhuang]

Hello,

       I still has some question about the SPI_AP:

       1、Does external microcontroller not must be another SJA1110, S32G274A has SPI access also can be the external microcontroller?

      2、On SPI_AP, boot step also load image from SPI flash, run over the init and static config process, etc.  as same as the SPI_HOST mode, then what will the external microcontroller do about the ethernet switch?  

     3、In my understand that the boot and load image will controlled by external microcontroller, SJA1110 only provides ethernet switch to external microcontroller as hardwares

[PavelL]

Hello @yangjinzhuang ,

ad 1. External controller can be anyone. I use my laptop & FTDI driver to access my SJA1110 EVM board.

ad 2. Once you load image from SPI FLASH, the external microcontroller is not necessary at all. SJA1110 can work fully autonomously. External microcontroller could monitor traffic, diagnostic registers, ... 

ad 3. SDL boot is also supported option.

Best regards,

Pavel

[yangjinzhuang]

Hello,

       Thanks for your reply, from um549820-UM11107 software UM, I got that SPI_HOST and SPI_AP are multiplexed, because SPI_HOST is used to control the processor boot, then if I set SPI_AP and switch is controlled by external microcontroller, so I understand that SPI_AP has an impact on boot step, maybe my understand is not right, so I need your help to confirm.

       1、I see my hardware, the dip switch SW12[1] is on and SW12[2] is off in default, it's boot mode is NVM boot and boot from SPI flash. If I use SPI_AP, then the boot mode as default can also boot success, it will not boot fail because of not SPI_HOST?

       2、About SPI_AP, I can get form UM111107 that two SJA1110, one SJA1110 is controlled by another SJA1110, but I am not sure that: can I use S32G274A as an external microcontroller to control SJA1110 through SPI_AP？In this case NVM boot can still boot success from SPI flash？

[PavelL]

Hello @yangjinzhuang ,

Usage of SPI_AP does NOT affect boot from SPI FLASH.

ad 1. After reset, the SJA110 reads pin strapping options and boots from SPI FLASH. Then you can access SPI_AP at your will - reading registers, dynamically changing configuration, ...

ad 2. You can use 32G274A as an external microcontroller to control SJA1110 through SPI_AP. Yes, the NVM boot will still succeeded.

Best regards,

Pavel

[yangjinzhuang]

Hello,

        Thank you very much, I am now clearly understand the SPI_AP and boot process.

At last, I am not sure about the SWITCH_CONTROL_INTERNAL and SWITH_CONTROL_SPI mode in SDK,  do I need to config it to SWITH_CONTROL_SPI if I want to work on SPI_AP access, I see it set to SWITCH_CONTROL_INTERNAL as default in SDK.

[PavelL · Accepted solution]

Hello @yangjinzhuang ,

you need to say to SDK, how the switchcore can be accessed.

Then internal routines (like SWITCH_DRV_Read) take care of that automatically.

If you are developing firmware for SJA1110's internal M7, SWITCH_CONTROL_INTERNAL shall be set.

If you are developing firmware for SJA1110's internal M7 to access external switchcore (cascaded SJA1110), SWITH_CONTROL_SPI shall be used:

I guess it will be about the same if you are developing firmware for S32G to control SJA1110 over SPI. I need to double check it. You have created another thread on that, so I will answer there. Thank you for your patience.

Best regards,

Pavel

[yangjinzhuang]

Hello,

       Thank you for your reply, yes, I have asked in another topic "SJA1110 SDK for the hardware GLDBOX". Maybe we can discuss there.