A resource burner for (not only) standalone system
pik33
Posts: 2,416
We have a 16 MB flash memory on every(?) P2 board.
So instead of adding cog drivers and resources in a DAT or asm shared sections they can be stored in the flash area and loaded on demand,
There is a topic about flash and SD access at the same time: https://forums.parallax.com/discussion/175020/flash-and-microsd-in-the-same-program-how-to-flexprop#latest
First experiments with the burner using available flash object ended with unformatting the (unmounted, unused) SD card in the Edge's slot. I managed to restore the card, but it means the flash access has to be done in Mode 3 or it is not safe for a SD card and I have to add erase and write procedures to the read procedure from the topic mentioned above.
Here is the simple bitbanged Mode 3 flash object:
' A simple bitbanged SPI Mode 3 flash driver
' v. 0.02 - 2022.12.08
' Piotr Kardasz pik33@o2.pl with a help from the P2 community
' read a block (256 bytes) from the flash
' fa - flash address, ha - hub address
pub read_block(fa,ha) | bb,i
org
drvh #60 ' clock
drvh #61 ' cs
drvh #59 ' prop->flash
fltl #58 ' flash->prop
add fa, ##$03000000 ' 03-read
outl #61 ' select the flash
rep @p1, #32 ' send command+address
rol fa, #1 wc
outl #60
outc #59
outh #60
p1 mov pr0,#64 ' read 64 longs
outl #60
fltl #59
outh #60
p3 rep @p2, #32
outl #60
rcl fa, #1
outh #60
testp #58 wc
p2 rcl fa, #1
movbyts fa,#%00011011
wrlong fa, ha
add ha, #4
djnz pr0, #p3
drvh #61 ' disable chip select
end
' erase a 4k block at fa
pub erase_block(fa)
org
drvh #60 ' clock
drvh #61 ' cs
drvh #59 ' prop->flash
fltl #58 ' flash->prop
mov pr0,##$06000000 ' write enable
outl #61
rep @p6,#8
rol pr0,#1 wc
outl #60
outc #59
outh #60
p6 nop
outh #61
waitx ##$30_000
add fa, ##$20000000 ' 20-erase 4k block
and fa, ##$FFFFF000 ' address has to be block aligned
outl #61 ' select the flash
rep @p1, #32
rol fa, #1 wc
outl #60
outc #59
outh #60
p1 nop
outh #61
waitx ##$30_000_000
fltl #59 ' prop->flash
end
pub write_block(fa,ha)
org
drvh #60 ' clock
drvh #61 ' cs
drvh #59 ' prop->flash
fltl #58 ' flash->prop
mov pr0,##$06000000
outl #61
rep @p6,#8
rol pr0,#1 wc
outl #60
outc #59
outh #60
p6 nop
outh #61
waitx ##$30_000
add fa, ##$02000000 ' 02 - write 256 bytes block
outl #61 ' select the flash
rep @p1, #32
rol fa, #1 wc
outl #60
outc #59
outh #60
p1 mov pr1,#256
p3 rdbyte pr0,ha
shl pr0,#24
rep @p2,#8
rol pr0, #1 wc
outl #60
outc #59
outh #60
p2 add ha,#1
djnz pr1,#p3
outh #61
waitx ##3_000_000
fltl #59 ' prop->flash
drvh #60
end
The burner now burns the HDMI cog driver, font and sprites definition. In the final version I want to have any possible stuff needed for a standalone system: audio drivers, samples, etc.
Comments
Very cool.
Can you give a example how to load the HDMI driver from Spin and/or (better) PASM once it is in the Flash, and have you some sort of Directory/Index in mind?
Very useable idea, I like it much.
Enjoy!
Mike
No, I have no directory, I only prepared a flash memory map
I am now in the process of rewriting the spin code, but this works:
A perecompiled cog code is loaded now from the flash instead of attaching it as DAT section.
This $70000 is the unused memory. Used for testing, the proper way is to allocate 4k of memory, do job, then free it.
This driver uses also a font definitions. In the current state 3 definitions are attached as DAT. I can now preload one of them from the flash on demand and not keeping all of them in the hub.
PSRAM 32 MB driver for P2-EC32MB added to the burner. Burns at $860000. Attached psram_flash.spin2 is a modified version of the high level PSRAM driver file that loads it from the flash instead of using a PASM/Spin driver source code. It uses $7F000 as a temporary storage, but any HUB RAM can do, you need only to adjust the driver address variable
driverAddr:= $7F020which is HUB RAM driver start+$20. Afer the driver is started, the HUB RAM can be discarded and reused