HD6845P datasheet anyone?

[arnoldemu]

I am looking for the HD6845P datasheet.
My KC Compact has one in it and I was wondering how much/little I am going to get with it. I hope it's not equivalent to a type 2!!!!

I've run some simple crtc tests on it, but nothing yet to tell me more about vsync etc and the other tell tail signs.

So far I found:
1. R8 delay doesn't exist. So you can't turn on the border when you want with it.
2. disptmg doesn't exist. So you can't shift the screen a bit.
3. R3: You definitely can't do soft scroll with it. Screen never moves regardless of the value I put into it. (didn't try really low values though).
4. Blue Angel 69 and Sudoku run fine 

I'll do some more tests later.

BTW, KC compact doesn't have CPC's "mode 3", and it seems doing an IN to the  CRTCs data port effectively does a write. Also, I tried to load and run a simple basic program that plays around with reg 8 and the KC Compact just locked up. No idea why.

Markus will be happy, I used his cdt2wav to load some stuff into it

[Bryce]

I have it here, but it's too big to attach, send me a PM with your e-mail address.
 
  Bryce.

[Bryce]

It should be in your inbox now

Bryce.

[Gryzor]

Just a question - what's that HDblahblah thingie?

Other than that, maybe it's worth it upping it to the wiki to have?

[robcfg]

Well, the 6845 is the CRT controller in our beloved CPC, and the HD is the Hitachi prefix. The lat P indicates something but should be in the datasheet itself.


I think it's worth having it in the wiki along with the other CRTC types' datasheets.

[arnoldemu]

It should be in your inbox now

Bryce.

received with thanks.

[Gryzor]

Well, the 6845 is the CRT controller in our beloved CPC, and the HD is the Hitachi prefix. The lat P indicates something but should be in the datasheet itself.


I think it's worth having it in the wiki along with the other CRTC types' datasheets.

Damn! I knew about the 6845, but the entire code thew me off Doesn't the CPC have an original Motorola controller though?


[Edit] Hey, Wikipedia says that it was cloned indeed by Hitachi as the 46505...

[arnoldemu]

Damn! I knew about the 6845, but the entire code thew me off Doesn't the CPC have an original Motorola controller though?

The CPC had 3 different CRTC (note I didn't include cpc+ here):

HD6845SP (type 0) - Hitachi
UM6845R (type 1) - UMC
MC6845 (type 2) - Motorola
Cost-down (type 4) - Amstrad

It is claimed that some may have MC6845*2.

Well this kc compact has HD6845P. This seems to be similar to a type 1, but I'm going to check to find out more.

[Gryzor]

Aha... never thought of it that way - I thought they were just different revisions, not clones by different manufacturers... thanks.

[Octoate]

The datasheets are already available in the CPC Wiki in the CRTC article.

[arnoldemu]

Some info from testing on kcc (so some are kcc hardware related):

Seems to be a HD6845R but it's not named like this on the packaging:

- vsync length fixed at 16 lines
- hsync 4/5 produce smooth r3 scroll it seems
- hsync width of 5 or more doesn't move screen
- hsync of 0 = 16 but some crazy lines happen on left side and screen wobbles like crazy
the screen moves left and right a few pixels and scanline black lines are on the left side, but it's not stable.
- all hsync widths cause interrupt
- vertical counter increments through vertical adjust it seems
- because /iord and /iowr enable crtc, then you can write to crtc with an in. data on bus is latched into crtc
(Seems the same is true of CPC, Aleste and CPC+)
- no disptmg (so no r8 scrollers)

out &bc00,0:print inp(&bd00) will set r0 to 255 on CPC and KCC.
On CPC+ it puts something like 0x076 or 0x075.

I've not tested any demos yet. It seems to be type 0 or type 1 in terms of compatibility.

When I loaded Sudoku, the normal loading stripes appeared. The picture is going from SCART to CPC+ monitor but not well, because the image is ghosted. But I think I saw little dots over the picture (where the colour change would probably happen). 1 pixel or so.

mode 3 doesn't show black, it shows a single colour. Not sure which yet, may be the last colour shown.. or may be colour 1... not tested fully yet.

[arnoldemu]

When I loaded Sudoku, the normal loading stripes appeared. The picture is going from SCART to CPC+ monitor but not well, because the image is ghosted. But I think I saw little dots over the picture (where the colour change would probably happen). 1 pixel or so.

mode 3 doesn't show black, it shows a single colour. Not sure which yet, may be the last colour shown.. or may be colour 1... not tested fully yet.

The dots may be caused from a bug in the hardware, the schematics seem to indicate that the colour could be set incorrectly for 1 pixel when using the border. But i need to check.

Mode 3 shows last colour output, because the pixel clock is stopped.
(5V is passed to the shift register and not a clock signal).