Hi Paul: I am actually trying to figure out the hardware SPI module for F-RAM. So can you share your codes for that part? I appreciate it very much!!!Originally Posted by prstein
Vinson
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Hi Paul: I am actually trying to figure out the hardware SPI module for F-RAM. So can you share your codes for that part? I appreciate it very much!!!
Vinson
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Hello Vinson,
Here it is, warts and all...
Let us know if there are questions or difficulties.Code:'**************************************************************** '* Name : HW_FRAM_SPI_Test.pbp * '* Notes : Demo of using hardware SPI port to read and write * '* : a Ramtron FM25C106-G 16K 5V F-RAM chip. * '* : * '* : Assembled on an Olimex DEV-00021 40-pin * '* : board from Sparkfun. * '* : * '* : Much information on working with the hardware * '* : SPI was gleaned from Jeremy Grotte's * '* : sdfshc32d.pbp file. * '* : * '* : Compiled using PBP v2.60L * '* : * '**************************************************************** ' PIC18F452 DIP Package ' Pin Assignments ' Pin # Use Hookup ' 1 MCLR/VPP To Vdd through 4.7k resistor ' 2 RA0/AN0 n/c, reserved for analog input ' 3 RA1/AN1 n/c ' 4 RA2/AN2/VREF- n/c ' 5 RA3/AN3/VREF+ n/c ' 6 RA4/T0CKI n/c ' 7 RA5/AN4/SS n/c ' 8 RE0/RD/AN5 n/c ' 9 RE1/WR/AN6 n/c ' 10 RE2/CS/AN7 n/c ' 11 Vdd Power, +5V ' 12 Vss Ground ' 13 OSC1/CLKIN To 20MHz crystal ' 14 OSC2/CLKOUT To 20MHz crystal ' 15 RC0/T1OSO/T1CKI n/c ' 16 RC1/T1OSI/CCP2 n/c ' 17 RC2/CCP1 n/c ' 18 RC3/SCK/SCL to F-RAM SCK (pin 6) ' 19 RD0/PSP0 n/c ' 20 RD1/PSP1 n/c ' 21 RD2/PSP2 n/c ' 22 RD3/PSP3 FRAM_CS, to F-RAM CS (pin 1) ' 23 RC4/SDI/SDA SDI, to F-RAM SO (pin 2) ' 24 RC5/SDO SDO, to F-RAM SI (pin 5) ' 25 RC6/TX/CK TX; to MAX232A Pin 11 (goes out from pin 14 to DB9F pin 2) ' 26 RC7/RX/DT RX; to MAX232A Pin 12 (goes out from pin 13 to DB9F pin 3) ' 27 RD4/PSP4 n/c ' 28 RD5/PSP5 n/c ' 29 RD6/PSP6 n/c ' 30 RD7/PSP7 n/c ' 31 Vss Ground ' 32 Vdd Power, +5V ' 33 RB0/INT n/c ' 34 RB1 n/c ' 35 RB2 n/c ' 36 RB3/PGM n/c ' 37 RB4 n/c ' 38 RB5 n/c ' 39 RB6/PGC n/c ' 40 RB7/PGD n/c 'Notes '----- 'SETUP RS232: 'Target device uses 115200 baud, 8 bits, 1 stop bit, flow control = none '-------------------------------------------------------------------------------- '### Includes '-------------------------------------------------------------------------------- 'none '-------------------------------------------------------------------------------- '### Defines '-------------------------------------------------------------------------------- DEFINE LOADER_USED 1 DEFINE OSC 20 'Set receive register to receiver enabled DEFINE HSER_RCSTA 90h 'Set transmit register to transmitter enabled, high speed BRGH DEFINE HSER_TXSTA 24h 'Set baud rate DEFINE HSER_BAUD 115200 'automatically clear any USART overflows DEFINE HSER_CLROERR 1 '-------------------------------------------------------------------------------- '### Constants '-------------------------------------------------------------------------------- TRUE CON 1 FALSE CON 0 OCWREN con %00000110 'F-RAM Write Enable Op-Code OCRDSR con %00000101 'F-RAM Read Status Register Op-Code OCWRSR con %00000001 'F-RAM Write Status Register Op-Code OCREAD con %00000011 'F-RAM Read Memory Op-Code OCWRITE con %00000010 'F-RAM Write Memory Op-Code '-------------------------------------------------------------------------------- '### Aliases '-------------------------------------------------------------------------------- SCK Var PORTC.3 ' SPI clock SCK_TRIS Var TRISC.3 ' SPI clock direction SDI Var PORTC.4 ' SPI data in SDI_TRIS Var TRISC.4 ' SPI data in direction SDO Var PORTC.5 ' SPI data out SDO_TRIS Var TRISC.5 ' SPI data out direction FRAM_CS Var PORTD.3 ' F-RAM chip select FRAM_CS_TRIS Var TRISD.3 ' F-RAM chip select direction WCOL Var SSPCON1.7 ' SSP write collision SSPEN Var SSPCON1.5 ' SSP enable SSPIF Var PIR1.3 ' SSP interrupt flag '-------------------------------------------------------------------------------- '### Set Up Registers '-------------------------------------------------------------------------------- ADCON1 = %10001110 'left justified, RA0/AN0 is analog input 'Set up SPI port SSPSTAT = %01000000 ' Sample at middle of data output time, Transmit on idle rising edge of SCK 'SSPCON1 = %00000010 ' SPI master mode, clock = Fosc/64, Clock idle LOW. 'SSPCON1 = %00000001 ' SPI master mode, clock = Fosc/16, Clock idle LOW. SSPCON1 = %00000000 ' SPI master mode, clock = Fosc/4, Clock idle LOW. SSPEN = 1 ' Enable hardware SPI port. '-------------------------------------------------------------------------------- '### Variables '-------------------------------------------------------------------------------- nSPI_Data_In var byte nSPI_Data_Out var byte lVal var long wFRAM_Addr var word '-------------------------------------------------------------------------------- '### Initialization '-------------------------------------------------------------------------------- FRAM_CS = 1 ' F-RAM chip not selected. FRAM_CS_TRIS = 0' F-RAM chip select as output SDO = 1 ' Start SPI data out high SDO_TRIS = 0 ' SPI data out as Output SDI_TRIS = 1 ' SPI data in as Input SCK = 0 ' SPI clock idles low SCK_TRIS = 0 ' SPI clock as Output wFRAM_Addr = $000F ' Set an arbitray memory location lVal = -5000 ' Set lVal to some starting point pause 500 hserout["lVal initalized to ", dec lVal,13,10] 'Jump to Main program goto main '-------------------------------------------------------------------------------- '### Helper Functions '-------------------------------------------------------------------------------- WriteSPI: WCOL = 0 nSPI_Data_In = SSPBUF ' Clear the buffer. SSPIF = 0 ' Clear the interrupt flag. SSPBUF = nSPI_Data_Out ' Send the byte. If (WCOL) Then Return ' Check for write collision. While (!SSPIF) ' Wait for send to complete. Wend Return ReadSPI: nSPI_Data_In = SSPBUF ' Clear the buffer. SSPIF = 0 ' Clear the interrupt flag. SSPBUF = $ff ' Shift out a dummy byte. While (!SSPIF) ' Wait for receive byte. Wend nSPI_Data_In = SSPBUF ' Get the byte. return '-------------------------------------------------------------------------------- '### MAIN PROGRAM '-------------------------------------------------------------------------------- Main: ' Do a write ' Select the F-RAM FRAM_CS = 0 ' Begin with WREN nSPI_Data_Out = OCWREN gosub WriteSPI ' un-select the F-RAM FRAM_CS = 1 ' only one Op-code per chip select!!! ' Select the F-RAM FRAM_cs = 0 ' Next send WRITE OpCode nSPI_Data_Out = OCWrite gosub WriteSPI ' Send two bytes of address (upper 5 bits are "don't care") nSPI_Data_Out = wFRAM_Addr.HighByte '$00 gosub WriteSPI nSPI_Data_Out = wFRAM_Addr.LowByte '$0f gosub WriteSPI ' next byte(s) are data, address will increment with each write nSPI_Data_Out = lVal.Byte0 gosub WriteSPI nSPI_Data_Out = lVal.Byte1 gosub WriteSPI nSPI_Data_Out = lVal.Byte2 gosub WriteSPI nSPI_Data_Out = lVal.Byte3 gosub WriteSPI ' un-select the F-RAM FRAM_CS = 1 ' do a read FRAM_CS = 0 ' Begin by sending the read OpCode nSPI_Data_Out = OCREAD '=READ command gosub WriteSPI ' Send two bytes of address (upper 5 bits are "don't care") nSPI_Data_Out = wFRAM_Addr.HighByte gosub WriteSPI nSPI_Data_Out = wFRAM_Addr.LowByte gosub WriteSPI ' Now read in the value one byte at a time gosub ReadSPI 'one byte into nSPI_Data_In lVal.Byte0 = nSPI_Data_In gosub ReadSPI 'one byte into nSPI_Data_In lVal.Byte1 = nSPI_Data_In gosub ReadSPI 'one byte into nSPI_Data_In lVal.Byte2 = nSPI_Data_In gosub ReadSPI 'one byte into nSPI_Data_In lVal.Byte3 = nSPI_Data_In FRAM_CS = 1 hserout["lVal=",dec lVal,13,10]; ' Add one and write it back to the same location lVal = lVal + 1 goto Main
Best Regards,
Paul
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Thanks Paul for your shared codes!!! It is great.
I did the same test, but used PIC16LF877(3.0V) and FM25V10(3.0V,1Mbit). I think the communication is the same, only with some minor modifications. I spent almost one day on it,still get no result yet.... Can you help me to check if there is anything wrong with it?
Thanks!
Code:'**************************************************************** '* Name : HARDWARE_SPI_FRAM TEST.BAS * '* Author : [select VIEW...EDITOR OPTIONS] * '* Notice : Copyright (c) 2010 [select VIEW...EDITOR OPTIONS] * '* : All Rights Reserved * '* Date : 3/17/2010 * '* Version : 1.0 * '* Notes : * '* : * '**************************************************************** '**************************************************************** Define OSC 10 'INCLUDE "modedefs.bas" DEFINE LOADER_USED 1 Define LCD_DREG PORTD Define LCD_DBIT 4 Define LCD_RSREG PORTE Define LCD_RSBIT 0 Define LCD_EREG PORTE Define LCD_EBIT 1 Low PORTE.2 ' LCD R/W line low (W) ADCON1 = %10000010 ' Set PORTA analog and right justify result Pause 500 ' Wait .5 second Low PORTE.2 ' LCD R/W line low (W) ADCON1 = %10000010 ' Set PORTA analog and right justify result Pause 500 ' Wait .5 second Ticks VAR word ' Tick count (61 ticks = 1 sec) Hour VAR byte ' Hour variable Minute VAR byte ' Minute variable Second VAR byte ' Second variable Disp VAR byte ' Disp = 1 to update display ' Interrup handling bits GIE var INTCON.7 PEIE var INTCON.6 TMR2IE VAR PIE1.1 TMR2ON VAR T2CON.2 TMR2IF VAR PIR1.1 ' Definations for the SPI communication protocal '------------------------------------------------------------------ 'TRISB.5=0 ' This is for the CS PIN FM_CS VAR PORTA.5 ' SPI FRAM CHIP CS PIN FM_CS_TRIS VAR TRISA.5 ' SPI FRAM CHIP CS PIN DIRECTION SCK VAR PORTC.3 ' SPI CLOCK SCK_TRIS VAR TRISC.3 ' SPI CLOCK PIN DIRECTION CONTROL SDI VAR PORTC.4 ' SPI DATA IN SDI_TRIS VAR TRISC.4 ' SPI DATA IN PIN DIRECTION SDO VAR PORTC.5 ' SPI DATA OUT PIN SDO_TRIS VAR TRISC.5 ' SPI DATA OUT PIN WCOL VAR SSPCON.7 'SSP WRITE COLLISION SSPEN VAR SSPCON.5 'SSP ENABLE SSPIF VAR PIR1.3 'SSP INTERRUPT FLAG '--------------------------------------------------------------------- '-----------------------A/D setups -------------------------------------------- 'Define ADC_BITS 10 ' Set number of bits in result 'Define ADC_CLOCK 2 ' Set clock source (3=rc) 'Define ADC_SAMPLEUS 20 ' Set sampling time in uS 'TRISA = %11111111 ' Set PORTA to all input 'ADCON1 = %10000010 ' Set PORTA analog and right justify result '------------------------------------------------------------------------------- '-------------SPI PORT REGISTERS SETUP---------------------------------------- SSPSTAT=%01000000 ' SAMPLE AT THE MIDDLE OF DATA OUTPUT TIME, TRANSMIT ON IDLE RISING EDGE OF SCK SSPCON=%00100000 ' SPI MASTER MODE, CLOCK=Fosc/4 ENABLE HARDWARE SPI PORT SSPEN=1 ' ENABLE HARDWARE SPI PORT '------------------------------------------------------------------------------- '---VARIABLES FOR THE ADDRESS AND DATA MANAGEMENT------------------------------- 'TX_LEN CON 1 'SENDING DATA LENGTH TX_BUFF var byte'[TX_LEN] 'SENDING DATA ARRAY 'RX_LEN CON 1 'RECEIVING DATA LENGTH RX_BUFF var byte'[RX_LEN] 'RECEIVING DATA ARRAY ADD VAR WORD 'ADDRESS FOR THE MOMEORY(LOW 16BITS) BLOCK0 VAR BYTE 'HIGH EIGHT BITS OF MEMORY ADDRESS BLOCK1 VAR BYTE 'HIGH EIGHT BITS OF MEMORY ADDRESS '------------------------------------------------------------------------------- '-------------INITIALIZATION-------------------------------------------------- FM_CS=1 'FRAM CHIP DISABLED FM_CS_TRIS=0 'OUTPUT SDO=1 'START SPI PIN WITH HIGH SDO_TRIS=0 'OUTPUT SDI_TRIS=1 'INPUT BLOCK0=%00000000; BLOCK1=%00000001; add=0; B0 Var byte b0=100; X1 VAR BYTE X2 VAR BYTE X3 var BYTE X4 var BYTE 'Delay VAR byte ‘ Used to Debounce button 'TRISA = 0 ‘ PORTA is output 'TRISB = 3 ‘ RB0,RB1 are inputs 'CMCON = 7 ‘ PORTA digital I/O 'PAUSE 500 ‘ Wait 0.5sec for LCD to initialize ' ' Clear Hour, Minute, Second and Ticks to zero ' Hour = 0 Minute = 0 Second = 0 Ticks = 0 ' T2CON=%01001100 ' Set the prescaler to 1, and postscale to 10 ON INTERRUPT GOTO ISR ' ISR routine 'PR2=156 ' Set PR2 Register 10ms for timer2 'PR2=249 ' Set PRS2 Register PR2=224' Set PR2 Resiger for 1ms timer2 GIE=1 PEIE=1 TMR2IE=1'Enable the Timer2 interrupt. TMR2ON=1' ' Defines for the SPI-Control Registers '------------------------------------------------------------------------------------- TRUE con 1; FALSE CON 0; CONT_WREN CON %00000110 'F-RAM WRITE ENBALE OP-CODE CONT_RDSR CON %00000101 'F-RAM READ STATUS REIGSTER OP-CODE CONT_WRSR CON %00000001 'F-RAM WRITE STATUS REGISTER OP-CODE CONT_READ CON %00000011 'F-RAM READ MOMEORY OP-CODE CONT_WRITE CON %00000010 'F-RAM WRITE MEMORY OP-CODE '------------------------------------------------------------------------------------- LOOP: '-------Write the OP-CODE and the three Bytes of address----- FM_CS=0 TX_BUff=cont_WREN gosub writespi fm_cs=1 fm_cs=0 tx_buff=cont_write gosub writespi '-----send three bytes of address------------- tx_buff=block0; gosub writespi tx_buff=add.byte1 gosub writespi tx_buff=add.byte0 gosub writespi '----------------------Write the first four bytes the desired data-------------- tx_buff=$02 gosub writespi tx_buff=$03 gosub writespi tx_buff=$04 gosub writespi tx_buff=$05 gosub writespi FM_CS=1 ADD=0 '----------------------Read the four bytes------------------------------------ fm_cs=0; tx_buff=cont_read gosub writespi '------------------Sending three byts of address--------------------------- tx_buff=block0; gosub writespi tx_buff=add.byte1 gosub writespi tx_buff=add.byte0 gosub writespi '-----------------Read data into the variables------------------------------- gosub readspi x1=rx_buff gosub readspi x2=rx_buff gosub readspi x3=rx_buff gosub readspi x4=rx_buff 'hserout [dec4 hour]; 'hserout [dec4 Minute]; 'hserout [dec4 Ticks]; 'hserout [hex ]; 'hserout [dec4 ]; 'hserout [dec4 ]; 'hserout [dec4 ]; IF Disp = 1 THEN LCDOUT $FE, 2 LCDOUT hex X1, ":",hex X2, ":",hex x3,":",dec4 Ticks PAUSE 20 ENDIF Disp = 0 'PAUSE 1000 GOTO LOOP '-----------------Sub routines for the SPI write and read----------------------- WriteSPI: WCOL=0 Rx_buff=SSPBUF ' CLEAR THE BUFFER SSPIF=0 ' CLEAR THE INTERRUP FLAG SSPBUF=tx_buff ' SEND THE BYTE IF(wcol) THEN RETURN WHILE(!SSPIF) WEND SSPIF=0; RETURN ReadSPI: rx_buff=SSPBUF ' Clear the buffer SSPIF=0 ' Clear the interrup flag SSPBUF=0 ' Shift out a dummy byte What is this? while(!sspif) ' wait for receive byte wend rx_buff=SSPBUF ' Get the byte return DISABLE ISR: 'pause 3 'pauseus 400 'TMR2ON=0' TURN OFF TMR2 Ticks = Ticks + 1 'IF Ticks < 4 THEN NoUpdate ' ' 1 second has elapsed, now update seconds and if necessary minutes and hours. ' if Ticks=1000 then ticks=0 Second = Second + 1 ' Update second IF Second = 60 THEN Second = 0 Minute = Minute + 1 ' Update Minute IF Minute = 60 THEN Minute = 0 Hour = Hour + 1 ' Update Hour IF Hour = 24 THEN Hour = 0 ENDIF ENDIF ENDIF endif Disp = 1 ' Set to update display ' ' End of time update ' NoUpdate: TMR2IF=0 ' Re-enable TMR2 interrupts Resume ENABLE ' Re-enable interrupts END END ' End of program
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One Mbit? Now I have chip envy.
It looks like you need to add "FM_CS=1" right before the line "IF Disp = 1 THEN". The F-RAM never gets un-selected after the read.
It couldn't be that simple, could it? If that's not it please provide detail about what it is and is not doing correctly. If all else fails make sure it works using SHIFTIN and SHIFTOUT. If that fails as well use an o-scope to confirm ALL of the pins on the F-RAM are in their proper states.
Best Regards,
Paul
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Thanks Paul:-)
Really it is not quite easy. Last time it took me several days to find out the problem with SHIFTIN SHIFTOUT. I am sure the chip is working with those commands. But you know it is too slow... That's why I am switching to use the the hardware SPI to make it faster...
I will test it see what I can get..
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Still with no results... The reads I get for the four variables are all zeros. I mean X1 to X4.It seems like there are response from SDO. But never get anything in SDI from the os-scope. It is weird...
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This may help for HW SPI (From 877A datasheet):
"Any write to the SSPBUF register during transmission/reception of data will be ignored and the write collision detect bit, WCOL (SSPCON<7>), will be set. User software must clear the WCOL bit so that it can be determined if the following write(s) to the SSPBUF register completed successfully."
The following:
Can be changed to this:WriteSPI (read-modify-write):
WCOL=0
Rx_buff=SSPBUF ' CLEAR THE BUFFER
SSPIF=0 ' CLEAR THE INTERRUP FLAG
SSPBUF=tx_buff ' SEND THE BYTE
IF(wcol) THEN RETURN
WHILE(!SSPIF)
WEND
SSPIF=0;
RETURN
ReadSPI:
rx_buff=SSPBUF ' Clear the buffer
SSPIF=0 ' Clear the interrup flag
SSPBUF=0 ' Shift out a dummy byte What is this?
while(!sspif) ' wait for receive byte
wend
rx_buff=SSPBUF ' Get the byte
return
WriteSPI (write-receive-read):
SSPIF=0 ' CLEAR THE INTERRUP FLAG
WCOL=0 ' CLEAR COLLISION BIT BEFORE WRITING TO SPI
SSPBUF=tx_buff ' SEND THE BYTE
WHILE(!SSPIF) ' WAIT FOR 8-BITS TO BE CLOCKED-OUT/CLOCKED-IN - THIS HAPPENS SIMULTANEOUSLY
WEND
Rx_buff=SSPBUF ' STORE RECEIVED DATA
SSPIF=0 ' CLEAR THE INTERRUP FLAG
RETURN
ReadSPI:
SSPIF=0 ' CLEAR THE INTERRUP FLAG
WCOL=0 ' CLEAR COLLISION BIT BEFORE WRITING TO SPI
SSPBUF=0 ' SEND/CLOCK-OUT DUMMY BYTE TO CLOCK-IN RECEIVED BYTE
WHILE(!SSPIF) ' WAIT FOR 8-BITS TO BE CLOCKED-OUT/CLOCKED-IN - THIS HAPPENS SIMULTANEOUSLY
WEND
Rx_buff=SSPBUF ' STORE RECEIVED DATA
SSPIF=0 ' CLEAR THE INTERRUP FLAG
return
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