Feature #7
openImplement I2C vga/hdmi support
Added by admin over 7 years ago. Updated almost 7 years ago.
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Description
Try the I2C support on the new board.
Initially for presence detection
Latest for checking modes
Its via a mux chip so we can independently address both ports
Files
PCA9540B.pdf (290 KB) PCA9540B.pdf | foft, 05/11/2017 08:26 PM | ||
24c04.pdf (163 KB) 24c04.pdf | foft, 05/11/2017 08:27 PM | ||
ddcciv1r1.pdf (127 KB) ddcciv1r1.pdf | foft, 05/11/2017 08:30 PM |
Updated by foft over 7 years ago
- File PCA9540B.pdf PCA9540B.pdf added
Attached mux/level converter chip data sheet
Updated by foft over 7 years ago
Used this controller for the ADC on v1: https://eewiki.net/pages/viewpage.action?pageId=10125324
So I guess I just need to wire this to the ZPU, then I can experiment with this in firmware.
I guess a write FIFO that captures 16 bits (7 bit address, R/W and data). Then a fifo for the reply. + A way of telling when its all stopped.
Updated by foft over 7 years ago
- Related to Bug #19: PAL VGA Synch issues (screen is not centered added
Updated by admin almost 7 years ago
- Priority changed from Normal to Urgent
Going to at least check this chip is wired properly before the new boards are ordered
Updated by foft almost 7 years ago
Writing some code to say:
select channel1
read selected channel
write to random slave on channel1
select channel0
read selected channel
write to random slave on channel0
Might be working, but need to work out how to check... I guess I can stick the scope in i2c decode mode on the vga or hdmi port (fiddly...) and see if I see anything.
Updated by foft almost 7 years ago
Picoscope has i2c debugging and linux drivers:-) Installed them and will connect that up and take a look tomorrow.
Updated by foft almost 7 years ago
Looking on signaltap looks like slave reads of the control register are not working. Hmmm.
Updated by foft almost 7 years ago
I had the pin assignments backwards. I can now write 4/5 to the control register and read it back. This should be channel select.
Next up... checking that what I write makes it to the VGA and HDMI port. I guess I could try speaking to them. Annoying thing here is I only have one monitor so would need to disconnect it to check!
Updated by foft almost 7 years ago
VGA is working... receiving “00 FF FF FF FF FF FF 00 10 AC …"
Now for HDMI
Updated by foft almost 7 years ago
HDMI is working too... “00 FF FF FF FF FF FF 00 10 AC …
Updated by foft almost 7 years ago
- Priority changed from Urgent to Normal
Setting back to normal since the hardware side is working fine.
Updated by foft almost 7 years ago
Added to the video settings 'VGA connected' and 'HDMI connected' which look for the start of the DDC sequence '00FF'