AM335x GPMC asynchronous timing is strange

Robinson lei

Intellectual 600 points

CPU: AM335X

I use GPMC Asynchronous access NOR flash

GPMC_FCLK frequency = 100Mhz

TIMEPARAGRANULARITY = 0h

GPMC_CONFIG2_0 = 0x70701;

CSRDOFFTIME = 0x7

CSWROFFTIME = 0x7

CSONTIME =0x1

I was using this formula: For single read: A = (CSRdOffTime – CSOnTime) × (TimeParaGranularity + 1) × GPMC_FCLK

when TimeParaGranularity = 0x0;

A= (7 - 1) * (0 + 1) * 10ns

= 60ns

but ,By testing the value of the CS signal time effectively is "120ns"

I was depressed for a long time.

Is there any problem with my setting?

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

What software are you using?

0 Robinson lei over 9 years ago in reply to Biser Gatchev-XID

Intellectual 600 points

500Mhz oscilloscope and uboot 2014 from TI,s SDK.

0 Biser Gatchev-XID over 9 years ago in reply to Robinson lei

TI__Guru**** 393215 points

Please post all GPMC register settings.

0 Robinson lei over 9 years ago in reply to Biser Gatchev-XID

Intellectual 600 points

They can't get access to the device ID.

#define STNOR_GPMC_CONFIG1 0x1200

#define STNOR_GPMC_CONFIG2 0x70701

#define STNOR_GPMC_CONFIG3 0x30301

82 #define STNOR_GPMC_CONFIG4 0xE040602

84 #define STNOR_GPMC_CONFIG5 0x70808

85 #define STNOR_GPMC_CONFIG6 0x7070280

87 #define STNOR_GPMC_CONFIG7 0x40

***********************************************************

65 #define STNOR_GPMC_CONFIG1 0x1200

66 #define STNOR_GPMC_CONFIG2 0xF0F01

67 #define STNOR_GPMC_CONFIG3 0x30301

68 #define STNOR_GPMC_CONFIG4 0xE040E04

70 #define STNOR_GPMC_CONFIG5 0xC0F0F

71 #define STNOR_GPMC_CONFIG6 0x7070280

73 #define STNOR_GPMC_CONFIG7 0x40

0 Biser Gatchev-XID over 9 years ago in reply to Robinson lei

TI__Guru**** 393215 points

Which ones? why are they defined 2 times?

0 Robinson lei over 9 years ago in reply to Biser Gatchev-XID

Intellectual 600 points

This is it

Two sets of timing I have made a test

#define STNOR_GPMC_CONFIG1 0x1200

#define STNOR_GPMC_CONFIG2 0x70701

#define STNOR_GPMC_CONFIG3 0x30301

#define STNOR_GPMC_CONFIG4 0xE040602

#define STNOR_GPMC_CONFIG5 0x70808

#define STNOR_GPMC_CONFIG6 0x7070280

#define STNOR_GPMC_CONFIG7 0x40

0 Biser Gatchev-XID over 9 years ago in reply to Robinson lei

TI__Guru**** 393215 points

Check your GPMC_CONFIG4 to GPMC_CONFIG6 values. They seem wrong. Can you try with these values:

#define STNOR_GPMC_CONFIG4 0x6030603
#define STNOR_GPMC_CONFIG5 0x50808
#define STNOR_GPMC_CONFIG6 0x5040280

0 Robinson lei over 9 years ago in reply to Biser Gatchev-XID

Intellectual 600 points

OK Tank you very much.

I will try it.

0 Robinson lei over 9 years ago in reply to Biser Gatchev-XID

Intellectual 600 points

Hello Biser Gatchev-XID:

I test the following "GPMC" configuration or can not get the device ID

#define STNOR_GPMC_CONFIG1 0x1200
#define STNOR_GPMC_CONFIG2 0x70701
#define STNOR_GPMC_CONFIG3 0x30301
#define STNOR_GPMC_CONFIG4 0x6030603
#define STNOR_GPMC_CONFIG5 0x50808
#define STNOR_GPMC_CONFIG6 0x5040280
#define STNOR_GPMC_CONFIG7 0x40

can you tell me？

There are some reasons that cause the values of the configuration and test values not a same.

AM335X At OSC0 of 25MH, I'm not sure if 25MHZ has a impact.

By testing the value of the CS signal time effectively is "120ns"