sample code for M25P32

[Pedro Santos]

Hello

Have anyone sucessfull used the M25P32 serial memory device?
Perhaps a sample code to share?

Thank You

Best regards

pedro

[BrianT]

Hi Pedro,
I have used the M25P32 with good success. Here are some code snips as pointers.

In essence I build an array of 4 x 64 characters and then burst them into the memory. I do this 4 times per record so I store 1024 bytes each logging sample period.

Heavily cut to fit the 10k character limit but I am sure you can nut it out.

HTH
Brian



DEFINE osc 4 '20
'DEFINE NO_CLRWDT 1
DEFINE Loader_Used 1
DEFINE DEBUG_REG PORTC 'Debug pin port
DEFINE DEBUG_BIT 6 'Debug pin bit
DEFINE DEBUG_BAUD 19200 'Debug baud rate
DEFINE DEBUG_MODE 0 'Debug mode: 0 = True, 1 = Inverted
'DEFINE DEBUG_PACING 100 'Debug character pacing in us

'****************** Variables **************************
' RAM Assignments and Variables
' -----------------------------
MEMchip var byte ' either 0 or 1 to
ADval var word 'Create adval to store result
DB var byte ' Single Data Byte to be passed to memory
DB2 var byte
DS0 var byte[64] ' String of data bytes to be passed to memory
DS1 var byte[64] ' String of data bytes to be passed to memory
DS2 var byte[64] ' String of data bytes to be passed to memory
DS3 var byte[64] ' String of data bytes to be passed to memory
UZ var word
Addr0 var byte ' LSB of 24 bit address
Addr1 var byte
Addr2 var byte ' MSB of 24 bit address

'*************************** Hardware assigns

'PortD
CLK var portd.0 ' Clock to both M25P32
MD var portd.1 ' Data to both M25P32
MQ var portd.2 ' Data from both M25P32
MS0 var portd.3 ' Chip 0 Select - active LOW
MS1 var portd.4 ' Chip 1 Select - active LOW - idle HIGH
SpareD5 var portd.5 ' spare
SpareD6 var portd.6 ' spare
SpareD7 var portd.7 ' spare
TRISD = %00000100
PortD = %00011110


'**************************** Subroutines *****************************
goto endsubroutines ' jump subroutines at startup

WakeUpMemory: 'M25P32
' Release from deep power down
TRISA = %00000001
TRISB = %11101111 'SDA, SCL, Thermistor, MicPwr, nc, nc, nc, nc
TRISC = %10000000 'Rx232, Tx232 & LED, MW0, MS1, MD, MC, MemPwr1, MemPwr0
TRISD = %11100001 'SDA2, SCL2, Alarm, MW1, MS0, MH1, MH0, MQ
ADCON0 = %11000001 'ADC enabled
' ADCON1 = %10000010 ' 10 bit resolution - use ADRESH & ADRESL
ADCON1 = %00000010 ' 8 bit resolution IF ADRESH is used as adVal
high clk
high md
input mq
high sda
high scl
low micpwr
high tx232
high ms0
high ms1
' Mem 0 - Release from Deep Power Down
low ms0
high ms1
shiftout md, clk, 1, [$AB, $AA, $AA, $AA ] 'wake needs 3 dummy bytes
shiftin mq, clk, 0, [db] '
high ms0
high ms1
pause 1
' Mem 1 - Release from Deep Power Down
high ms0
low ms1
shiftout md, clk, 1, [$AB, $AA, $AA, $AA ] 'wake needs 3 dummy bytes
shiftin mq, clk, 0, [db] '
high ms0
high ms1
pause 1
return


'****************** end of subroutines ****************************
EndSubRoutines:
'********************** Initialise ********************************

''ZZZZZZZZZZZZZ Run from here ZZZZZZZZZZZZZZZZZZ
ReadActionFlag:
read 0,af
if af = 0 then erasemem ' followed by log data AF = 2
if af = 1 then memdump ' followed by end
if af = 2 then logdata ' followed by dump memory AF = 1
if af = 3 then waitfornewcode ' followed by end

'********************************* Erase Memory ***************************
EraseMem:
gosub wakeupmemory 'set up TRIS etc & release from deep power down

'Remove write protection by writing to Status Register
low ms0
low ms1
'Issue WRite ENable before status register write
shiftout Md, clk, 1, [$06 ] ' WREN issued to BOTH chips
high ms0
high ms1
pauseus 10
' Write to both Mem0 & Mem1 Status Register
low ms0
low ms1
shiftout Md, clk, 1, [$01,$00 ]' Write Status Reg, clear protection bits
high ms0
high ms1
pause 16 ' tw is 15

' Issue Bulk erase command
low ms0
low ms1
'need a WRite ENable before the bulk erase command
shiftout Md, clk, 1, [$06 ] ' WREN issued to BOTH chips
high ms0
high ms1
pauseus 10
low ms0
low ms1
shiftout Md, clk, 1, [$C7]' Bulk Erase command to BOTH chips
high ms0
high ms1
c = 0
EraseCheck: 'loop at 1/sec until erase complete
c = c + 1
low ms0 'select Mem0
high ms1
shiftout md, clk, 1, [$05] 'Read Status Register
shiftin mq, clk, 0, [a]
a = a & %00000001 ' extract bit 0
high ms0
high ms1
pauseus 10
high ms0
low ms1 'select Mem1
shiftout md, clk, 1, [$05]
shiftin mq, clk, 0, [b]
b = b & %00000001
high ms0
high ms1
pause 1000 'nominal 1 second loop
debug #c, ",", #a, ",", #b ," "
if c//15 = 0 then debug $0D, $0A
if c > 250 then end
if (a = 0) or (b = 0) and c < 15 then
debug $0D, $0A, "Premature WIP flag clear - retrying", $0D, $0A
pause 1000
goto erasemem
endif
if (a = 1) or (b = 1 ) then erasecheck 'not finished yet
debug $0D, $0A, $0D, $0A, " Erase times VALID - PASS", $0D, $0A

''*************** Memory Dump ***********************
MemDump:
addr0 = 0 'LSB byte address - 256 entries
addr1 = 0 ' page address - 256 entries
addr2 = 0 'MSB sector address - 64 entries in M25P32 128 in M25P64
high ms0
high ms1
for memchip = 0 to 1 ' do it for both memory chips
for addr2 = 0 to 63 ' 64 sectors per chip
for addr1 = 0 to 255 ' 256 pages per sector each with 256 bytes
' Wake from deep power down
if memchip = 0 then
low ms0
high ms1
pauseus 10
else
high ms0
low ms1
pauseus 10
endif
shiftout Md, clk, 1, [$AB, $AA, $AA, $AA ] 'wake from deep power down
shiftin mq, clk, 0, [db] ' DB is chip identifier - discarded
high ms0
high ms1
pause 1
' Select Memory Dump mode
if memchip = 0 then
low ms0
high ms1
pause 1
else
low ms1
high ms0
pause 1
endif
shiftout Md, clk, 1, [$03, addr2, addr1, addr0 ] ' Select MemDump mode
xxxxxxxx snip xxxxxxxxxxxx

RecordingBlock:
' WakeUpMemory already called so should be ready to go
' select the correct memory chip
if addr2 < 64 then
low ms0
high ms1
else
high ms0
low ms1
endif
'Prepare to clear write protection bits
shiftout Md, clk, 1, [$06 ] ' WREN issued
high ms0
high ms1
if addr2 < 64 then
low ms0
high ms1
else
high ms0
low ms1
endif
shiftout Md, clk, 1, [$01,$00 ]' Write Status Reg, clear protection bits
high ms0
high ms1
pause 15 ' this is tw from datasheet

' Write a 4x1024 character blocks with data from various sources
CollectDataForPage0:
xxxxxxxxxxxxxxxxxxxxx snip xxxxxxxxxxxxxxxxx
'Now write the 256 bytes just collected to memory
'Program the page
'Prepare memory to accept data - issue WREN
if addr2 < 64 then
low ms0
high ms1
else
high ms0
low ms1
endif
shiftout Md, clk, 1, [$06 ] ' issue WREN
ms0 = 1 ' deselect both memory chips at end
ms1 = 1

if addr2 < 64 then
MS0 = 0 ' select memory 0
MS1 = 1
else
ms0 = 1
ms1 = 0
endif
shiftout md, clk, 1, [$02, addr2, addr1, addr0] ' issue Page Program command
' Write the first full page of 256 samples including time & date
for a = 0 to 63
shiftout md, clk, 1, [ds0[a]] ' write the date, time & heart sample
next a
for a = 0 to 63
shiftout md, clk, 1, [ds1[a]] ' write the heart sample
next a
for a = 0 to 63
shiftout md, clk, 1, [ds2[a]] ' write the heart sample
next a
for a = 0 to 63
shiftout md, clk, 1, [ds3[a]] ' write the heart sample
next a
MS0 = 1 'deselect both memory chips
MS1 = 1
' Page Program now running - increment pointers and
' buffer some heart samples into RAM
addr0 = 0 'byte address - set zero for justin
addr1 = addr1 + 1 'increment page address
if addr1 = 0 then addr2 = addr2 + 1 'increment sector address
'Stop completely at end of memory
if addr2 > 127 then end ' avoids overwriting old data