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SPI flash programmer code — Parallax Forums

SPI flash programmer code

cgraceycgracey Posts: 14,133
edited 2016-09-13 21:50 in Propeller 2
Here is a program you can run that will program a connected SPI flash with the OUTB blinker program.

If you put pull-ups on both spi_cs and spi_ck, it will work with the last release.

I found a bug in the 100ms timeout code in the ROM booter, where relative addressing was being used and I didn't realize it. I fixed this on my end, but I need to make new FPGA images to fix it on your end. If you use both pull-ups now, it will work.

This boot process takes about 15ms. Five milliseconds is spent reading 1KB from the flash, then ten milliseconds is spent validating it before executing it.
' Program SPI flash with signed OUTB blinker program
' - Connect SPI flash (M25P80 okay) with pull-ups on spi_cs and spi_ck
' - Blinks OUTB on boot-up

CON

  spi_cs = 61
  spi_ck = 60
  spi_di = 59
  spi_do = 58

DAT


		org
'
'
' Init SPI pins
'
		outh	#spi_cs

		dirh	#spi_cs
		dirh	#spi_ck
		dirh	#spi_di
'
'
' Erase 1st $1000 bytes
'
		call	#spi_wrena		'write enable

		mov	cmd,cmd_erase		'sector erase
		call	#spi_cmd32

		call	#spi_wait		'wait for completion
'
'
' Program first $400 bytes
'
		loc	ptra,#\pgmdata		'point to program data

.program	call	#spi_wrena		'write enable

		mov	cmd,cmd_program		'page program
		or	cmd,adr
		call	#spi_cmd32

.byte		rdbyte	cmd,ptra++		'get byte

		mov	x,#8			'send byte
		shl	cmd,#24
		call	#spi_out

		add	adr,#1			'page done?
		test	adr,#$FF	wz
	if_nz	jmp	#.byte

		call	#spi_wait		'wait for completion

		testb	adr,#10		wz	'another page?
	if_z	jmp	#.program
'
'
' Read data back to outa for viewing on logic analyzer
'
		mov	dira,#$1FF

.read1k		mov	cmd,cmd_read		'start read
		call	#spi_cmd32

		outh	#8			'trigger signal
		outl	#8

		decod	y,#10			'read byte to outa
.read		call	#spi_in
		setbyte	outa,cmd,#0
		djnz	y,#.read

		jmp	#.read1k		'loop
'
'
' SPI write enable
'
spi_wrena	mov	cmd,#$06		'write enable
		call	#spi_cmd8

		ret
'
'
' SPI wait while busy
'
spi_wait	mov	cmd,#$05
		call	#spi_cmd8

.wait		call	#spi_in
		test	cmd,#$01	wc
	if_c	jmp	#.wait

		ret
'
'
' SPI command
'
spi_cmd32	mov	x,#32
		jmp	#spi_cmd

spi_cmd8	mov	x,#8
		shl	cmd,#24

spi_cmd		outh	#spi_cs
		outl	#spi_cs
'
'
' SPI long/byte out (x=bits, cmd=msbdata)
'
spi_out		rep	@.r,x
		shl	cmd,#1		wc
		outc	#spi_di
		outh	#spi_ck
		outl	#spi_ck
.r
		ret
'
'
' SPI byte in (cmd)
'
spi_in		rep	@.r,#8
		outh	#spi_ck
		outl	#spi_ck
		testin	#spi_do		wc	'due to latencies, 'testin' is from 2 clocks before 'outh'
		rcl	cmd,#1
.r
		ret
'
'
' Data
'
cmd_erase	long	$20_00_00_00
cmd_program	long	$02_00_00_00
cmd_read	long	$03_00_00_00
adr		long	0
'
'
' Variables
'
cmd		res	1
x		res	1
y		res	1
'
'
' Program Data
'
' first 20 bytes are blinker program:
'
'	not	dirb
'.lp	not	outb
'	waitx	##20_000_000/4
'	jmp	#.lp
'
' last 32 bytes are signature (key=0)
'
	orgh

pgmdata	byte	$FB,$F7,$23,$F6,$FD,$FB,$23,$F6,$25,$26,$80,$FF,$28,$80,$66,$FD	'blinker program
	byte	$F0,$FF,$9F,$FD,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
	byte	$99,$AA,$44,$98,$86,$E2,$C8,$71,$C3,$1E,$60,$BF,$A3,$36,$19,$7A	'SHA-256/HMAC signature
	byte	$F5,$3D,$53,$97,$5C,$AF,$BA,$BB,$B7,$7F,$C3,$0A,$B4,$24,$02,$40

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Comments

  • How would I load an unsigned program from flash?

    nick
  • cgraceycgracey Posts: 14,133
    nglordi wrote: »
    How would I load an unsigned program from flash?

    nick

    All flash boot programs must be signed. That's how we tell if it's really a program, or just a bunch of random data, or that even a flash chip is really connected.
  • jmgjmg Posts: 15,148
    cgracey wrote: »
    Here is a program you can run that will program a connected SPI flash with the OUTB blinker program.
    If you put pull-ups on both spi_cs and spi_ck, it will work with the last release.
    This looks to be for a 1b connected device ?

    Can you do similar code for a Quad-Connected Flash, as that is likely to be much more common final usage.
    ie Boot and Pgm from a Quad-Connected part.

    IIRC it needs to define and control the extra pins, and needs to issue a Reset command.

    cgracey wrote: »
    This boot process takes about 15ms. Five milliseconds is spent reading 1KB from the flash, then ten milliseconds is spent validating it before executing it.
    How does that time vary with code-size ? Is it linear or is there some block-step involved in validate ?

  • cgraceycgracey Posts: 14,133
    edited 2016-09-15 01:06
    jmg wrote: »
    cgracey wrote: »
    Here is a program you can run that will program a connected SPI flash with the OUTB blinker program.
    If you put pull-ups on both spi_cs and spi_ck, it will work with the last release.
    This looks to be for a 1b connected device ?

    Can you do similar code for a Quad-Connected Flash, as that is likely to be much more common final usage.
    ie Boot and Pgm from a Quad-Connected part.

    IIRC it needs to define and control the extra pins, and needs to issue a Reset command.

    cgracey wrote: »
    This boot process takes about 15ms. Five milliseconds is spent reading 1KB from the flash, then ten milliseconds is spent validating it before executing it.
    How does that time vary with code-size ? Is it linear or is there some block-step involved in validate ?

    These are stimulating questions.

    About quad SPI, the pins would be connected as such:

    61 = SPI_CS
    60 = SPI_CK
    59 = SPI_DQ0 (DO for 1-bit)
    58 = SPI_DQ1 (DI for 1-bit)
    57 = SPI_DQ2 (WP for 1-bit)
    56 = SPI_DQ3 (HOLD for 1-bit)

    That would be adding two connections, pins 57 and 56, to make the extra data bits. Note that this makes the nibble (#6) MSB-LSB reversed. A single 'REV' instruction could be used before/after program/read long to reverse the bits. This allows nice compatibility with the 1-bit connection scheme.

    I'd rather not put nibble mode in the ROM, because it would insist that two more pins always be dedicated for quad SPI flash, when some customers would want just want the single-bit hookup. They could turn that mode on in their own booter code (part of PNut, eventually), if they want to load their main program very quickly. They could also use the streamer to move nibbles at Fclk/2, since the clock must be toggled high and low for each nibble. At 160MHz, that's 40MB/s or the whole 512k flash-->hub in 12.5ms.

    About the SHA-256/HMAC, the booter currently handles this on a post-load basis, but it could be made per-byte, as the data comes in. At 20MHz, it takes ~10ms/KB. At 160MHz, that will be ~1.25ms/KB. That's 0.64s/512KB. The user may be running some simpler checksum, or even decryption, instead.

    Once the booter is loaded from SPI flash, the user will still have access to the SHA-256/HMAC code. He can handle things however he wants. The flash booter is $F8 longs. It plops right in amid the ROM booter code and gets JMP'd to. It can pick up right from where the ROM booter left off, if it wants to. All the ROM booter code is still present and callable.
  • jmgjmg Posts: 15,148
    edited 2016-09-15 01:51
    cgracey wrote: »
    These are stimulating questions.

    About quad SPI, the pins would be connected as such:

    61 = SPI_CS
    60 = SPI_CK
    59 = SPI_DQ0 (DO for 1-bit)
    58 = SPI_DQ1 (DI for 1-bit)
    57 = SPI_DQ2 (WP for 1-bit)
    56 = SPI_DQ3 (HOLD for 1-bit)

    That would be adding two connections, pins 57 and 56, to make the extra data bits. Note that this makes the nibble (#6) MSB-LSB reversed. A single 'REV' instruction could be used before/after program/read long to reverse the bits. This allows nice compatibility with the 1-bit connection scheme.
    ...
    They could also use the streamer to move nibbles at Fclk/2, since the clock must be toggled high and low for each nibble.

    How does the streamer manage the reverse nibble you mentioned ?
    or do you mean use REV for commands and address, and skip for data R/W ?
    That would make 1b load code, different from Quad code, which could get messy ?
    cgracey wrote: »
    I'd rather not put nibble mode in the ROM, because it would insist that two more pins always be dedicated for quad SPI flash, when some customers would want just want the single-bit hookup. They could turn that mode on in their own booter code (part of PNut, eventually), if they want to load their main program very quickly.

    I'd agree ROM is ok in 1b mode, but it needs to issue a reset from Quad (which I think you have done ?)
    and the question about the WP and HOLD pins is does the user have to add external pullups, or can the ROM apply pullups, saving 2 parts on the BOM ?

  • Chip p58 and P59, are DO and DI from the flash chip point of view?

    If so, I think its the reverse of how the breakout boards are set up, but I'll check
  • I guess the existing breakout board compatability doesn't really matter much, anyway

    Here's a pcb layout for the signal order. Looks good.

    700 x 281 - 10K
  • cgraceycgracey Posts: 14,133
    Tubular wrote: »
    Chip p58 and P59, are DO and DI from the flash chip point of view?

    If so, I think its the reverse of how the breakout boards are set up, but I'll check

    It'll be fine.
  • Cluso99Cluso99 Posts: 18,069
    I mentioned what I thought was a good pinout that permitted
    SPI FLASH
    Quad SPI FLASH
    SD CARD SPI
    SD CARD quad

    Here is the link, with the pinout also repeated
    http://forums.parallax.com/discussion/comment/1386295/#Comment_1386295
    P63  RXD (SI = serial in)
    P62  TXD (SO = serial out)
         Flash...         |  SD...
    P61  #CE              |  DI  / CMD
    P60  CLK              |  CLK
    P59  (#HOLD) / SIO3   |  #CS / D3-CD
    P58  (#WP)   / SIO2   |  x   / D2
    P57  SO      / SIO1   |  x   / D1
    P56  SI      / SIO0   |  DO  / D0
    
    Note: The akward use of the CD pinout to permit possible use of quad mode CD at a later date.

    1. This permits the later use of QUAD SPI without the need to swap pins/bits around when using QUAD SPI.

    2. This also permits SD to be used on the same pins instead of (ie without) SPI.

    3. When accessing Flash normally (not Quad mode),#HOLD=1. This is compatible with the SD Card being deselected. Only if Flash was determined not to be present would the SD Card be tried.
  • cgraceycgracey Posts: 14,133
    cgracey wrote: »
    Tubular wrote: »
    Chip p58 and P59, are DO and DI from the flash chip point of view?

    If so, I think its the reverse of how the breakout boards are set up, but I'll check

    It'll be fine.

    Wait. Sorry. P59 needs to be DI and P58 needs to be D0. If that's not the case, the ROM code won't work.
  • cgraceycgracey Posts: 14,133
    edited 2016-09-15 08:27
    Cluso99 wrote: »
    I mentioned what I thought was a good pinout that permitted
    SPI FLASH
    Quad SPI FLASH
    SD CARD SPI
    SD CARD quad

    Here is the link, with the pinout also repeated
    http://forums.parallax.com/discussion/comment/1386295/#Comment_1386295
    P63  RXD (SI = serial in)
    P62  TXD (SO = serial out)
         Flash...         |  SD...
    P61  #CE              |  DI  / CMD
    P60  CLK              |  CLK
    P59  (#HOLD) / SIO3   |  #CS / D3-CD
    P58  (#WP)   / SIO2   |  x   / D2
    P57  SO      / SIO1   |  x   / D1
    P56  SI      / SIO0   |  DO  / D0
    
    Note: The akward use of the CD pinout to permit possible use of quad mode CD at a later date.

    1. This permits the later use of QUAD SPI without the need to swap pins/bits around when using QUAD SPI.

    2. This also permits SD to be used on the same pins instead of (ie without) SPI.

    3. When accessing Flash normally (not Quad mode),#HOLD=1. This is compatible with the SD Card being deselected. Only if Flash was determined not to be present would the SD Card be tried.

    That looks good, Cluso.

    I've been looking up current SPI flash offerings at Digikey and everything new seems to be quad SPI. I'm thinking maybe just dedicating 4 data pins, as you've shown, and always run in quad mode.

    So, you are pretty sure that your pinout permits concurrent connection of both quad SPI and SD card? That pinout certainly works well for quad SPI, alone. I don't know the specifics on the SD card, though.

    While perusing Digikey, I looked up the new Hyper RAM part. There are many Hyper flash chips, but only one Hyper RAM. They all have the same pinout, it seems. I wish they would have made that Hyper RAM with maybe 16MB of flash, as well. That would have solved everything (except SD).
  • Quad SPI is a waste of pins for me, I'd hardly use it. Seems a shame to waste another 3 pins just for those cases which somehow seem to need QSPI speed?
  • cgraceycgracey Posts: 14,133
    edited 2016-09-15 10:21
    Quad SPI is a waste of pins for me, I'd hardly use it. Seems a shame to waste another 3 pins just for those cases which somehow seem to need QSPI speed?

    I kind of agree. The soft reset process for the quad-supporting chips is to send commands $66 then $99. The trouble is, if you're in single-bit SPI mode, you send them one bit at a time, while if you're in quad SPI mode, you send them 4 bits at a time. Well, you don't know if the part is in single or quad mode in a warm boot.

    Micron offers a 'rescue' procedure to get a part back into single-bit mode, no matter what:
    The rescue sequence is composed
    of two parts that must be run in the correct order. During the entire sequence,
    tSHSL2 must be at least 50ns. The first part of the sequence is DQ0 (PAD DATA) and
    DQ3 (PAD HOLD) equal to 1 for the situations listed below:
    • 7 clock cycles within S# LOW (S# becomes HIGH before 8th clock cycle)
    • + 13 clock cycles within S# LOW (S# becomes HIGH before 14th clock cycle)
    • + 25 clock cycles within S# LOW (S# becomes HIGH before 26th clock cycle)
    The second part of the sequence is exiting from dual or quad SPI protocol by using the
    following FFh sequence: DQ0 and DQ3 equal to 1 for 8 clock cycles within S# LOW; S#
    becomes HIGH before 9th clock cycle.
    After this two-part sequence the extended SPI protocol is active.

    That procedure seems unique among manufacturers. I'm not clear, yet, on how we can be certain we're in single-bit mode.

    These different manufacturers use different sector sizes in their parts, too, which affects erase and program procedures. Not fun. I think we'll need to support several chips from PNut.exe. The 'programmer' will get downloaded using the text protocol, and then we'll send data fast to it, so that it programs the 2nd stage booter and the application data. Later, we can implement key-based encryption.
  • Cluso99Cluso99 Posts: 18,069
    Chip,
    The pin arrangement was not specifically designed for the use of both FLASH and SD. My thoughts were that you would boot FLASH or SD, but not both. If Flash exists, then that will have whatever other devices (including SD) and the location of the SD pins do not have to be shared.

    The pin out I have chosen permits D0-3 to be the correct way around and on a byte boundary. You will note I chose the SD to possibly permit the quad mode to be used providing there is an open source spec able to be used. No point in excluding this possibility for later.

    On the P1 where I have shared pins and been short of pins, I have had to use a single gate chip to assist with decoding.

    BTW did you ever get around to asking OnSemi about on chip Flash/OTP/EEPROM ?
  • RaymanRayman Posts: 13,900
    I think Kye figured out a long time ago that you just clock out a bunch of zeros and all the SQI chips go to SPI mode...
  • cgraceycgracey Posts: 14,133
    edited 2016-09-15 21:16
    I've been reading several SPI flash data sheets. I see no standard way of getting the part initialized after a reset. Most data sheets don't even talk about what to do about this problem. They also have differing commands to switch between single and quad modes. The only thing that looks reliable is read ($03) after power-up. There's also the problem of a SPI flash being in the middle of a program or erase, which could be a several-second process, in the case of a bulk erase. Trying to boot after a Prop2 reset from a SPI flash engaged in such a state wouldn't work. Any given SPI flash has a command to abort such a process, but these commands are unique to different chips. I'm seeing only one way to handle this problem: Power the SPI flash from an I/O pin, so that we can certainly get its attention. We'd drive power low for ~100us, then put it high and wait 1ms before reading. This is ugly, but it's the only reliable-looking solution, shy of specifying a certain manufacturer's SPI flash chip. What do you guys think?
  • RaymanRayman Posts: 13,900
    In my testing, the Kye method of just clocking in a bunch of zeros always worked...
  • RaymanRayman Posts: 13,900
    edited 2016-09-15 22:00
    But, I see this from Microchip appnote AN1797 for interfacing to Microchip devices:

    "If the bus mode is not known, the master device can transmit two RSTIO instructions using both the SDI and SQI formats to ensure a proper reset to SPI mode."

    The RSTIO instruction is 0xFF. Maybe there's some magic in being all 1's...

    Maybe I remembered wrong, maybe Kye's approach was to clock in 1's, not 0's. Have to check, been a while...
  • cgraceycgracey Posts: 14,133
    Rayman wrote: »
    In my testing, the Kye method of just clocking in a bunch of zeros always worked...

    Kye told me that he sent an $FF command three times. I don't see how that would do anything.
  • RaymanRayman Posts: 13,900
    See above, 0xFF is the RSTIO (reset I/O) command...
  • jmgjmg Posts: 15,148
    Rayman wrote: »
    Maybe I remembered wrong, maybe Kye's approach was to clock in 1's, not 0's. Have to check, been a while...

    I was about to say, surely that was a series of 1's ?
    The Micron scheme Chip mentions above, clocks in 1's but the CS# work also seems to infer a frame-check may exist on some devices ?

    Checking Winbond, I see they mention 0xff (8 Clocks) or 0xffff (16 clocks) for quad and dual exit respectively.
    Of course, they are unclear if you need both, to exit either, or not...
    They do explicitly mention 8 &16 clocks.
  • jmgjmg Posts: 15,148
    cgracey wrote: »
    Kye told me that he sent an $FF command three times. I don't see how that would do anything.

    See above, Winbond could be saying both are needed, in which case I'd send $ff 3 times, but actually framed as 8 + 16 - which seems closer to what Micron are getting at ?
  • jmgjmg Posts: 15,148
    edited 2016-09-15 23:18
    cgracey wrote: »
    .. Most data sheets don't even talk about what to do about this problem. They also have differing commands to switch between single and quad modes.
    I'd focus on the ones that do mention reset
    Fremont & Winbond & Adesto both say 0xff is reset, and Winbond & Adesto give 2 framings of 0xff and 0xffff for handling quad and dual exit.
    Those are all for smaller Flash sizes 16Mb region. - sub 20c parts, likely to be most commonly used for boot.

    Addit:
    For larger (eg) 256Mb sizes, I see Winbond and Micron have this to say (2 x 8 bit commands adjacent )

    “Enable Reset (66h)” and “Reset (99h)” instructions can be issued in SPI. To avoid accidental reset, both
    instructions must be issued in sequence. Any other commands other than “Reset (99h)” after the “Enable
    Reset (66h)” command will disable the “Reset Enable” state. A new sequence of “Enable Reset (66h)” and
    “Reset (99h)” is needed to reset the device. Once the Reset command is accepted by the device, the device
    will take approximately tRST=30us to reset.
    During this period, no command will be accepted.
    Data corruption may happen if there is an on-going or suspended internal Erase or Program operation when
    Reset command sequence is accepted by the device. It is recommended to check the BUSY bit and the
    SUS bit in Status Register before issuing the Reset command sequence.


    However, Micron also have a sticky XIP mode, that can skip commands (just sends nibble address), which is closer to HyperFLASH, and they also add this gem:
    It is recommended that the device exit XIP mode before executing these two commands to initiate a reset.
    Hmm, not easy for watchdog reset to cover that ?

    Digging more, finds Xp is output on DQ0, 7th clock, as Confirm XIP
    Xb is the XIP confirmation bit and should be set as follows: 0 to keep XIP state; 1 to exit XIP mode and return to standard read mode.
    - ie, 0xff here on DQ0 would exit XIP sticky.

    Suggests 0xff, 0xffff, 0x66, 0x99 (30us) might work on everything ?
    cgracey wrote: »
    Power the SPI flash from an I/O pin, so that we can certainly get its attention. We'd drive power low for ~100us, then put it high and wait 1ms before reading. This is ugly, but it's the only reliable-looking solution, shy of specifying a certain manufacturer's SPI flash chip. What do you guys think?
    Best avoided, if possible as that sounds like its own can of worms...

  • RaymanRayman Posts: 13,900
    I have a feeling there's an agreement for all to use $FF as reset I/O, and the same commands for JEDEC ID read and also for SPI data read...
  • jmgjmg Posts: 15,148
    Rayman wrote: »
    I have a feeling there's an agreement for all to use $FF as reset I/O, and the same commands for JEDEC ID read and also for SPI data read...
    Not quite, see the comments above on newer, larger parts having a specific 0x66 0x99 sequence.
    However the 0xff is still useful to exit XIP, before issuing the reset.

    Question is, do smaller parts tolerate those 0x66 x99 commands, which seem to be non allocated.
    Easy enough to test I guess.
  • RaymanRayman Posts: 13,900
    Just found there is an ofni group standard for commands, shared by many manufacturers

    One of the shared commands is reset, $ff
  • RaymanRayman Posts: 13,900
    And reset command must be accepted even if device is busy
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2016-09-16 00:26
    I'd be quite happy to work with one type of readily available Flash that could also be burnt from an F11. It's not like we'd be using different kinds P2 chips from different manufacturers either, so therefore I'd treat the Flash as part of the P2. I'm using the original Winbond W25Q80BV at present but I'm happy to scrap the tube of them for something else if need be.

    As for being unable to reset certain modes then perhaps you could "allow" (not mandatory) for extra I/O but I find that kludgy. At some point an SD only boot would fail too if I didn't have it inserted :)
  • Cluso99Cluso99 Posts: 18,069
    Heck, this sounds worse than SD :(

    FWIW to initialise an SD from an unknown state, they say (and Kye does) send 74 clocks with MOSI (DI) = 1's. Reading his code looks like that is 74 x $FF (ie 74*8).

    I have been looking at the Spansion/Cypress S25FL116KOXMFI043 family from Mouser (0.39/100). What is interesting with these parts are they can replace the ~$15 Altera Flash chips used on Cyclone IV & V (others too???) for configuration.

    Chip, can you investigate putting some Flash/OTP/Eeprom on chip with OnSemi? It could solve a lot of problems, depending on cost of course.
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