retrodev.info
Proudly wasting this domain name since 2001!Archive for jxd301
MakeLDR v1.0
Hello there!
Here you have a .LDR creation tool, meanwhile I code a quick minimal SDK for the Blackfin PMPs.
MakeLDR creates a valid JXD301 firmware from a given plain binary file (homebrew). The given binary is injected into a known previous firmware at a known address (0×80000). This is a workaround while we find a better way to do our own firmware.
Big thanks go to Orkie, Mithris and RobBrown for his previous work.
More JXD301 news…
It has been a few weeks since my last JXD301 dev report. Mithris managed to get his JTAG working, added BF support to it, disassembled the FW upgrader, and managed to get some graphics on screen through JTAG. Pretty amazing if you ask me. By the other hand, LiraNuna just pointed us to a very interesting development page. Stay tuned.
JXD301 development report
The JXD301 dev scene is moving slowly, but pointing to the right direction.
Mithris has managed to disassemble the firmware, and found that Block9 seems to being loaded to 0xffa00000, and thus gets booted first, then it inits some stacks and appears to play around with the MMU a bit. He also found block 2 etc, are loaded into RAM, so the initial bootloader must have an initblock that sets that stuff up, so probably that little program at 0xffa00000 is the one responsible for switching applications, etc.
Meanwhile, RobBrown has received his JXD301 and took some very high detailed inner photographs #1 #2 #3 #4 #5 #6 (warning: each photo is 2.5 mbytes sized!). Interestingly there are a few unsoldered points in photograph #6, which might lead to a communication interface.
Just got my JXD 301!
Ah, finally! And does it worth its money? Absolutely yes.
Here you have my first impressions:
- Very nice: screen resolution, brightness and wide angle of vision. handheld light weight. quality beyond common chinese PMPs. firmware quite solid. handheld specs. sound quality through headphones. 2 jacks in a single handheld. sd support (probably SDHC too). 2 Gbytes Flash RAM. extras (headphones, usb cable, usb adaptor, velvet-ish bag case). extras from mp4nation (very well packed, copy from ainol firmware english instructions, european jack voltage adaptor, total price including VAT and shipping costs is 92 eur, declared for customs as usb drive/gift/100$ value).
- Nice: quality through speaker. buttons responsiveness.
- To improve: buttons layout, d-pad style (not *that* bad though), delivering time (17 days waiting for it!).
- What’s wrong: number of buttons, no L/R buttons, emulation and movie software quality (might be much better), audio white noise when using headphones and reading from disk (it seems a software/firmware issue to me).
And here you have some photos done with JamQue’s mobile (thanks man!):
JXD301 runs at 500 MHz
The JXD guys have confirmed me in an e-mail that the 301 is using a 500 MHz Blackfin CPU, so we lose 100 MHz ! Doh ! :S
Blackfin crazyness!
Ok got my JXD 301 ordered through mp4nation.net guys. The whole joke was 92 eur (a little more expensive than expected, even using the discount coupon).
Mithris and me are finding the Blackfin DSP series very interesting: division stuff, hardware loops, address generators, etc.
I have to say that I love that ASM syntax! [SP--] = R0 makes me wet!
Meanwhile, time to wait a few days… sigh T_T
A nice new toy
I came across a new handheld/PMP yesterday while surfing the net: the JXD301, featuring a 600 MHz (!) BF533 CPU, probably 64 Mb RAM, 2 GB flash, SD support, 3.0” awesomely bright TFT, rechargeable battery, 2 headphone jacks, DIVX/FLAC/APE/WMA/MP3/OGG player and 90 eur shipping and VAT included. Yes, a 90 eur bargain. It seems a good candidate for my xmas present to me, isn’t it?.
!
(images from google images 
Meanwhile I’ve found some links of (dev)interest:
Last firmware:
Latest JXD-301 firmware
LDR hex-editing:
LDR viewer 1.2
Compilers:
Several gcc toolchains (linux)
GCC toolchain (win32)
VisualDSP++ 5.0
Benchmark tests:
BF533 @ 600 benchmark results
Documentation:
Programming Techniques for DSPs
BF533 PRM 1.1 (pdf)
LDR boot rom
uclinux:
Website
FB sample code
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