P4080ds Nor Flash Page Access

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P4080ds Nor Flash Page Access

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yaseryurtcan
Contributor II

Hi,

I have p4080ds board. I want to increase read speed from NOR Flash in order to meet system requirements. I have measured read speed around 10 MByte/sec. I think this speed is too low. I have searched it on internet and found that NOR Flash has two mode; word and page mode. Page mode is faster than word mode. I assume that NOR flash is in word mode. I have learned that by default elbc is in GPCM mode which does not support page mode access. In order to use page mode access UPM mode should be defined. I have searched and finally found that CS_SYS_FLASH_BR_PRELIM, which is base register definition.I think I need to set CS_SYS_FLASH_BR_PRELIM and CS_SYS_FLASH_OR_PRELIM the followings 

#define CONFIG_SYS_FLASH_BR_PRELIM (BR_PHYS_ADDR(CONFIG_SYS_FLASH_BASE_PHYS + 0x8000000) | BR_PS_16 | BR_V | 0x00000080)

#define CONFIG_SYS_FLASH_OR_PRELIM (OR_UPM_AM | OR_UPM_BCTLD | OR_UPM_BI | OR_UPM_TRLX | OR_UPM_EHTR | OR_UPM_EAD)

However, the board does not boot. So, what is the problem by using UPM mode? Is there anything I need to do?

Best regards.

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r8070z
NXP TechSupport
NXP TechSupport


Have a great day,

The BR/OR settings is not enough. You also should configure the UPMA itself i.e. set UPM mode register and write accesses patterns into UPMRAM. See upmconfig(uint upm, uint *table, uint size) in the mpc8xxx/fsl_lbc.c. The pattern has to be suitable for connected NOR flash.

The UPM burst read can generate flash page read, hence the NOR page size should be equal to the UMP burst size (32 bytes). The UPM executes burst read when core cache or DMA require for the burst access and burst inhibited BI is cleared in the OR.

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280 Views
yaseryurtcan
Contributor II

Thanks for the information. Are BR/OR settings that I have changed correct? If they are correct, as you stated I need to change more settings.

Best regards.

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