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arritsas
Joined: 16 Feb 2012
Posts: 4
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| PIC24FJ128GA006 with a extern flash memory |
 Posted: Wed Feb 22, 2012 3:00 am |
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Hello,
I am newbie with a 24FJ128GA006 PIC and I would like to know how I have to initialized the SPI in order to use it to send and received blocks of data from a SST25vf family's device.
I have used this line in order to declared the SPI params.
#USE SPI (MASTER, SPI1,BAUD=16000000,DO = PIN_F3,DI = PIN_F2,CLK = PIN_F6, MODE=0, BITS=8, STREAM=FLASH_STREAM)
Am I forgetting anything or not taking into account something?
I want to use the driver included in ccs and its functions, called sst25vf.c.
What I am exactly trying...
| Code: |
#include <24FJ128GA006.h>
#include <sst25vf.c>
#FUSES NOWDT //No Watch Dog Timer
#FUSES HS //Crystal osc 16MHz,High speed Osc (> 4mhz for PCM/PCH) (>10mhz for PCD)
#FUSES DEBUG //Debug mode for use with ICD
#FUSES NOWRT //Program Memory Write Protected
#FUSES NOIESO// #FUSES IESO //Internal External Switch Over mode enabled
#FUSES NOJTAG //JTAG disabled
#use delay(clock=32000000)
#define FLASH_STREAM SPI_1
#USE SPI (MASTER, SPI1,BAUD=16000000,DO = PIN_F3,DI = PIN_F2,CLK = PIN_F6, MODE=0, BITS=8, STREAM=FLASH_STREAM)
void main()
{
int aux;
int title;
ext_flash_init();//intialization of the comunication required
aux=0xF4;// a value which is going to be saved
ext_flash_write(0x000006, &aux,2);//writing in the flash
delay_ms(100);
ext_flash_read(0x000006,title,2);//reading from the flash the same direction
}
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Could someone help me? |
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FvM
Joined: 27 Aug 2008
Posts: 2337
Location: Germany
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| Posted: Wed Feb 22, 2012 3:45 am |
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A SPI clock of 16 MHz isn't available with 16 MHz CPU clock. I don't know, if #use spi selects the highest available clock frequency instead.
According to the comments in the sst25 driver, write protection must be unlocked before writing to the device. Please check. |
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arritsas
Joined: 16 Feb 2012
Posts: 4
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| Posted: Wed Feb 22, 2012 4:39 am |
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| FvM wrote: | A SPI clock of 16 MHz isn't available with 16 MHz CPU clock. I don't know, if #use spi selects the highest available clock frequency instead.
According to the comments in the sst25 driver, write protection must be unlocked before writing to the device. Please check. |
Ok, I have replaced the baud parameter. And changed it in order to take the default one.
But, I am not sure if I understand what you are telling about the write protection, do I must included the ext_flash_protect() function when I start the application? And if it like this unlock all the memory? |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19539
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| Posted: Wed Feb 22, 2012 9:16 am |
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I wouldn't explicitly select the IO pins. The syntax for #use SPI, is to _either_ specify the pins, _or_ use SPI1/SPI2, which automatically selects the corresponding hardware pins.
Unless you are using the stream parameter (which the library doesn't), I'd also not have a stream name. Particularly, since I'm not sure of having the name given as the stream name already #defined to something else.
The big one though is the write protection as Fvm points out. Look at the header of the driver:
"//// (Note that this flash protects all locations on power up) ////"
ext_flash_protect(FLASH_PROTECT_NONE);
needed after init, before doing anything else.
Best Wishes |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19539
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| Posted: Wed Feb 22, 2012 9:26 am |
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Just as a comment, I'd also select explicitly a 'legal' clock rate. I'd not be _sure_ the compiler would know that 1/1 and 1/1 for primary and secondary prescalers is 'invalid' at 16MHz (table 15-1 data sheet), so select 8MHz, which is the fastest available rate.
Best Wishes |
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