You are right, it is playing in mono! I don't use the old SDK anymore, Rockbox is
much easier to work with, the audio on my player is really perfect with Rockbox!
I now use Rockbox all the time. if you want to make themes I suggest building the Rockbox simulator
it works well and is easy to do.
I have another rk2706 player, from hacking the OF seems to be ILI9320 screen type, it's a touch screen clone of teclast M33.
I have put in all the screen setting but sadly the display does not work.
The data_transform setting I am not sure about.
The dump from OF is ROM:6003D488 sub_6003D488 ; CODE XREF: sub_6003D4AC+4p
ROM:6003D488 ; sub_6003D4C0+4p
ROM:6003D488 AND R1, R0, #0x3F000
ROM:6003D48C MOV R1, R1,LSR#2
ROM:6003D490 AND R2, R0, #0xFC0
ROM:6003D494 MOV R2, R2,LSR#4
ROM:6003D498 MOV R0, R0,LSL#26
ROM:6003D49C MOV R0, R0,LSR#24 (shift left 2?)
ROM:6003D4A0 ADD R1, R1, R2
ROM:6003D4A4 ADD R0, R0, R1,LSL#8
ROM:6003D4A8 BX LR
ROM:6003D4A8 ; End of function sub_6003D488
Which I have translated in lcdif-rk27xx.c as
unsigned int lcd_data_transform(unsigned int data)
unsigned int r, g, b;
/* 16 bit interface */
r = (data & 0x0003f000) >> 2;
g = (data & 0x00000fc0) >> 4;
b = (data & 0x0000001f) << 2;
#error "Unknown target"
return (r | g | b);
This could be wrong I am not sure.
I've got ili9320 working (my one is 320x240), but i can't get normal audio =) It's mono in Rockbox on either rf-8800 and rf-8900, so I'm very disappointed... I've even implemented FM radio and RTC, but can't figure out why audio is still mono... Code seems to be step-by-step identical with OF and recommendations from RK27xx datasheet, but it's still mono, not stereo. I don't like mono =)