Forum Discussion

Honored Contributor

16 years ago

Frame Reader Initialization

Hello,

I want to implement a Frame Reader which should read data from memory and send its AVALON Video protocol to an alpha blending mixer. My clocked video output settings for PAL are:

Image Width/Active pixels: 720

Image Height/Active lines: 576

Bits per Pixel per color planes: 8

Color plane transmission format: sequence

Interlaced Video

Pixel fifo size: 720

Fifo Level at which to start output: 719

Video in and out use the same Clock

Use control port

Sync signals: Embedded in video

Active picture line: 23

Horizontal blanking: 24

F rising edge line: 313

F falling edge line: 1

Vertical blanking rising edge line: 311

Vertical blanking: 25

I have written the value 128 to all corresponding addresses of the ram. For test purposes I am using the onchip ram for this. The RAM has two masters, the NIOS II and the frame reader. The settings of the frame reader are:

Bits per pixel per color plane: 8

Number of color planes in parallel: 1

Number of color planes in sequence: 2

Maximum Image width: 40

Maximum Image height: 40

Master port width: 64

Read master FIFO depth: 64

Read master FIFO burst target: 32

Use separate clock for the Avalon MM master interface: unchecked

(The data-width of the onchip RAM is 64.)

For initialisation of the frame reader I have written the following function which is called in once the main function of my NIOS II software:

void initFrameReader()

{

alt_printf("Initialize Frame Reader.\r\n");

// start Frame Reader

IOWR(FRAMEREADER_BASE, 0, 1);

// Frame Select

IOWR(FRAMEREADER_BASE, 3, 0);

// Frame 0 Base Address

IOWR(FRAMEREADER_BASE, 4, ONCHIP_MEM_BASE);

// Frame 0 Words

IOWR(FRAMEREADER_BASE, 5, 800); // 40*40 / ( 64/(8*4) ) = 800

// Frame 0 Single Cycle Color Patterns

IOWR(FRAMEREADER_BASE, 6, 6400); // 40*40*4 number of pixels in the frame multiplied by the number of single cycles required to represent one pixel

// Frame 0 Reserved

// IOWR(FRAMEREADER_BASE, 7, 0); // reserved for future use ?

// Frame 0 Width

IOWR(FRAMEREADER_BASE, 8, 40);

// Frame 0 Height

IOWR(FRAMEREADER_BASE, 9, 40);

// Frame 0 Interlaced

IOWR(FRAMEREADER_BASE, 10, 8); // See VIP Processing Suite - Table 4-4

}

But as soon as I Activate the Layer the Frame Reader corresponds to, I do not get a valid picture. Even if I deactivate it on runtime, it does not get a valid picture anymore. I have to reset the cpu to get the alpha blending mixer get work again (with frame reader layer deactivated).

What could be the problem? I have double-checked the BSP-Editor, none of my program memory addresses are placed on the onchip-mem. Could it be an arbitration problem? As far as I know the arbitration of the sopc-builder is round-robin and only requesting masters are included in the arbitration. But I am not writing data to the onchip memory while the frame reader is reading data from the RAM.

Could someone double-check the initialisation settings of the frame reader? Did I miss something, or did I missunderstand anything?

I would be pleased if anyone can helb me.

21 Replies

Altera_Forum
Honored Contributor
16 years ago
Ok, that is interesting. Indeed, there is no Interrupt connection from the cpu to the frame reader. How did you solve the issue that the "slave_av_irq" is not synthesized?

I have made the changes in the according source files in my quartus installation.
Altera_Forum
Honored Contributor
16 years ago
Changing the files in the Qartus folder and recompiling should work.

Perhaps you need to delete the db folder before recompiling?

Are you maybe using the MegaWizard to instantiate the frame reader? I found with the MegaWizard Quartus will copy the vfr files from the Quartus folder to your project folder. In this case you need to make sure the files in your project directory are also modified. When using SOPC builder, it will just reference the Quartus folder instead.
Altera_Forum
Honored Contributor
16 years ago
Here an update of my issue: I have tested your patch, kevin (only with service pack 1, which came out this week). The interrupt seems to fire now. Thank you for sharing this.

But still I do not get a valid picture (now the frame reader is ignored by the alpha blending mixer, nothing is shown). Did you do more changings to make the frame reader work? I will test the system by SignalTabs as soon as I am at work tomorrow morning and will give some more feedback.
Altera_Forum
Honored Contributor
16 years ago
The only change I made to the frame reader was the interrupt patch I posted. I installed 9.1 SP1 today and was a bit surprised to see they did not fix the interrupt issue.

Are you still trying to do interlaced video?

If yes, then the interlaced value you specify for the control packet would have to alternate every field. One tricky thing I ran into with the interrupt is that immediately after the interrupt fires, the frame reader will start the next frame, if it is still enabled, even before you service the interrupt and clear the flag. This makes it impossible to switch frames cleanly.

The solution is to clear the enable bit immediately after you set it. The frame read will finish the current frame even when you clear the enable bit. Then, when the interrupt fires, you can switch the frame setup cleanly. Reset the interrupt flag before momentarily re-enabling the frame reader.

To clear the interrupt:
IOWR(ALT_VIP_VFR_0_BASE, 2, 2);

To kick off the next (or first) frame:
IOWR(ALT_VIP_VFR_0_BASE, 0, 3);
IOWR(ALT_VIP_VFR_0_BASE, 0, 2);
Altera_Forum
Honored Contributor
16 years ago
I put the frequency of the onchip memory to 27 MHz and changed my interrupt service routine to the recomendations considering to clear the enable bit before sending out the next frame (thank you kevin). Now the frame reader can read data from the onchip memory and stream valid avalon video and data packets to the alpha blending mixer.

Altera has following workaround for the issue with the interrupt which is not connected, which I have tested successfully with the frame reader design reading data from onchip memory:

to fix the interrupt connectivity issue, you have to change the file "c:\altera\91
\ip\altera\frame_reader\src_hdl\alt_vipvfr91_vfr.v" on line 279
From: .interrupts (interrupts), To: .interrupts (irq_FROM_controller_TO_slave),

In Quartus II service pack 2 the issue will be solved.

I have also a design in which the onchip memory is replaced by a DDR SDRAM and instead of reading from the onchip memory it reads its data from the DDR SDRAM. However, there seem to be bandwith problems yet, since I can show a valid picture, with a limited width only.
Altera_Forum
Honored Contributor
16 years ago
Guys,

Your posts are very useful because the frame_reader is very problematic w/o informations.

Though I still have one problem:

Switching off/on the layer of graphics at Alpha Blending it flickers - randomly. The reason is that this core (the Alpha Belnding) does not care about field syncronization. As Altera states that, btw. So some external logic will be necessary to avoid somehow this issue.
Altera_Forum
Honored Contributor
16 years ago
Hello! I was really happy to find this thread, because I also have problems to configure the FrameReader. Unfortunately I can't adapt your comments for my case. It would be really nice if you help me.

I am trying to output Data from an onchip_memory (32bit) to a clocked_video_output in 1024x768. I have written "85" into all memory blocks. Now while reading I am using the following instanciation for the FreamReader:

// Frame Select IOWR(ALT_VIP_VFR_0_BASE, 3, 0); // Frame 0 Base Address IOWR(ALT_VIP_VFR_0_BASE, 4, ONCHIP_MEMORY2_1_BASE); // Frame 0 Words IOWR(ALT_VIP_VFR_0_BASE, 5, 196608); //1024*768*1/(32/8) // Frame 0 Single Cycle Color Patterns IOWR(ALT_VIP_VFR_0_BASE, 6, 2359296); //1024*768*1Cycle // Frame 0 Reserved // IOWR(FRAMEREADER_BASE, 7, 0); // reserved for future use ? // Frame 0 Width IOWR(ALT_VIP_VFR_0_BASE, 8, 1024); // Frame 0 Height IOWR(ALT_VIP_VFR_0_BASE, 9, 768); // Frame 0 Interlaced IOWR(ALT_VIP_VFR_0_BASE, 10, 3); // See VIP Processing Suite - Table 4-4 // start Frame Reader IOWR(ALT_VIP_VFR_0_BASE, 0, 1);
The goal later will be to write pixel data to the ram from different sources and then connect them from the ram to one tft, so that I can prebuilt the image in ram and pixelselect the sources. Therefore I want to use RGB in progressive and 1024x768.

My problems are the calculation of Words, Single Cycle Color Patterns and the right setting for Interlaced. It would be really nice if you could explain to me how I find out the number of cycles I need.

Thanks, Peter.
Altera_Forum
Honored Contributor
16 years ago
I really don't get it working. I was thinking that I have got the following conditions:

8bits per pixel per color plane
3 color planes in parallel
Master port width 64Bit
onchip_ram with 32bit width
width 1024
height 768

SingleCycleColorPattern => 1024x768 = 786432 (like p. 5-28 right bottom)
Words => width of a word is 64bit, one SingleCycleColorPattern has 24bit so i can get 2 SingleCycleColorPatterns in every word. => 786432 / 2 = 393216

Progressive Output means 0011 for 4bit InterlacingParameters (see Table 4-4) this means 3 (=>0011).

So now I tried:

// Frame Select IOWR(ALT_VIP_VFR_0_BASE, 3, 0); // Frame 0 Base Address IOWR(ALT_VIP_VFR_0_BASE, 4, ONCHIP_MEMORY2_1_BASE); // Frame 0 Words IOWR(ALT_VIP_VFR_0_BASE, 5, 393216); // Frame 0 Single Cycle Color Patterns IOWR(ALT_VIP_VFR_0_BASE, 6, 786432); // Frame 0 Reserved // IOWR(ALT_VIP_VFR_0_BASE, 7, 0); // Frame 0 Width IOWR(ALT_VIP_VFR_0_BASE, 8, 1024); // Frame 0 Height IOWR(ALT_VIP_VFR_0_BASE, 9, 768); // Frame 0 Interlaced IOWR(ALT_VIP_VFR_0_BASE, 10, 3); // start Frame Reader IOWR(ALT_VIP_VFR_0_BASE, 0, 1);

But it seems wrong. Does not work. Can anyone approve my calculations or has got a demo or example configuration? PLEASE.

Altera_Forum

Honored Contributor

16 years ago

Ok I have got it. I changed all MemoryMaster Width to 32Bit and then calculated:


// Frame 0 Single Cycle Color Patterns
IOWR(ALT_VIP_VFR_0_BASE, 6, 786432); //1024x768 = 786432 (like p. 5-28 right bottom)
// Frame 0 Single Cycle Color Patterns
IOWR(ALT_VIP_VFR_0_BASE, 5, 786432); 
//width of a word is 32bit, one SingleCycleColorPattern has 24bit so i can get 1 complete SingleCycleColorPatterns in every word. => 786432 / 1 = 786432

Altera_Forum
Honored Contributor
15 years ago
your post is very usful.
I use the frame reader in my design with the following settings:
Bits per pixel per color plane: 8
Number of color planes in parallel: 3
Number of color planes in sequence: 1
Maximum Image width: 1920
Maximum Image height: 1080
Master port width: 64
Read master FIFO depth: 1024
Read master FIFO burst target: 64
Use separate clock for the Avalon MM master interface: unchecked
Kindly confirm if the following calculations for number the words and the Single Cycle Color Patterns are true or not
1- // Words
IOWR(FRAMEREADER_BASE, 5, 259200); // (1920*1080*8*3)/48= 1036800

2- // Single Cycle Color Patterns
IOWR(FRAMEREADER_BASE, 6, 2073600); // 1920*1080=2073600 number of pixels in the frame

I apreciate your reply ASAP

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Frame Reader Initialization

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