On Mon, Mar 13, 2017 at 9:33 PM, Albert ARIBAUD albert.aribaud@free.fr wrote:
Hi Luke,
Le Mon, 13 Mar 2017 16:13:26 +0000 Luke Kenneth Casson Leighton lkcl@lkcl.net a écrit:
ah! albert! did you get my email, am looking to invite you to help with I2C EEPROM reading for the passthrough card (which has another STM32F072...)
Yes -- sorry I did not answer this week-end. Of course I'd be happy to help!
aawesome okaaayy here's the schematic: http://hands.com/~lkcl/eoma/passthrough/ EOMA68_PASSTHROUGH_3.pdf
i just realised i made a couple of mistakes, the reset "current-sinking-protecting-against-overvoltage" diode is the wrong way round, and the BOOT0 TP should be a 3.3v not ground oh well that explains a lot about why i can't see the damn thing on the USB bus after trying to reset it... :)
ok the primary task that's needed is: to read the VESA I2C EEPROM from the microdesktop board and to feed the resultant data out, on request, to the TFP401a. so it's two main parts:
* read (in bit-banging mode!) an I2C EEPROM * emulate an I2C EEPROM (probably best done via DMA and interrupts)
let's track it through - microdesktop pinouts: http://hands.com/~lkcl/eoma/microdesktop/ v1.7 schematic
microdesktop SCL 17 microdesktop SDA 22
and that goes through to....
GPIO_2 on passthrough schematic MCU_PWM0 on passthrough schematic
which are
PC6 (needing to be SCL) PA8 (needing to be SDA)
respectively.
the *secondary* task is that a userspace-programming firmware bootloader/uploader is needed... *on the USB* interface - the STM32F072 doesn't actually have one. i could have left BOOT0 pulled HIGH so that the STM32F072 always goes into bootloader mode but it may be needed for early power-on initialisation and to have some sort of "default" EDID response as well as bring up the TFP401a in cases where people simply don't upload firmware to it at all.
the first part is critical to the functionality i believe - a first prototype phase would be to just set up a static EDID buffer (static string) and return that as an emulated I2C EEPROM "read" operation.
btw if you haven't _got_ an I2C EEPROM of some kind (AT24C64) kicking around then perhaps simply wiring up two I2C interfaces back-to-back in DMA mode would do the trick :)
*really* appreciated your help here albert.
l.
sorry albert just checked the schematics and also watterott's HDMI_Display schematic - it's HDMI DDC that the STM32F072 needs to emulate! but looking at the watterott schematics that's just an EEPROM (again).
l.
Hi Luke,
Le Tue, 14 Mar 2017 07:32:17 +0000 Luke Kenneth Casson Leighton lkcl@lkcl.net a écrit:
sorry albert just checked the schematics and also watterott's HDMI_Display schematic - it's HDMI DDC that the STM32F072 needs to emulate! but looking at the watterott schematics that's just an EEPROM (again).
l.
OK, I'm lost :) and not really familiar with the passthrough card so let me try to find my bearings back; just stop me when I'm wrong. The goal is that the passthrough card advertise on its HDMI connector's I2C the display capabilities of the microdesktop it is slotted into. Correct?
So at the interface level, it should behave as an I2C slave EEPROM wrt DDC_SDA and DDC_SCL (that's I2C1 on the STM32) and as an I2C master wrt the EOM68 connector's I2C. Right?
Now, what I am not sure about yet is whether there are any conversion to be made between the I2C data read from the microdesktop(s I2C and the data to be provided on the HDMI DCC IC2.
Amicalement,
--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Thu, Mar 16, 2017 at 3:40 PM, Albert ARIBAUD albert.aribaud@free.fr wrote:
Hi Luke,
Le Tue, 14 Mar 2017 07:32:17 +0000 Luke Kenneth Casson Leighton lkcl@lkcl.net a écrit:
sorry albert just checked the schematics and also watterott's HDMI_Display schematic - it's HDMI DDC that the STM32F072 needs to emulate! but looking at the watterott schematics that's just an EEPROM (again).
l.
OK, I'm lost :) and not really familiar with the passthrough card so let me try to find my bearings back; just stop me when I'm wrong. The goal is that the passthrough card advertise on its HDMI connector's I2C the display capabilities of the microdesktop it is slotted into. Correct?
So at the interface level, it should behave as an I2C slave EEPROM wrt DDC_SDA and DDC_SCL (that's I2C1 on the STM32) and as an I2C master wrt the EOM68 connector's I2C. Right?
no, ignore the EOMA68 connector entirely - that has nothing to do with this.
the pins are the ones i listed. which is *NOT* the EOMA68 I2C pins. it's two *SEPARATE* pins which is why it really should be done as bit-banging.
Now, what I am not sure about yet is whether there are any conversion to be made between the I2C data read from the microdesktop(s I2C and the data to be provided on the HDMI DCC IC2.
nnnope! i would have said. it's very very simple. just straight "read EDID data from EEPROM then replay EDID data from EEPROM.".
that's all that's needed.
l.
Bonjour,
Le Fri, 17 Mar 2017 07:23:27 +0000 Luke Kenneth Casson Leighton lkcl@lkcl.net a écrit:
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Thu, Mar 16, 2017 at 3:40 PM, Albert ARIBAUD albert.aribaud@free.fr wrote:
Hi Luke,
Le Tue, 14 Mar 2017 07:32:17 +0000 Luke Kenneth Casson Leighton lkcl@lkcl.net a écrit:
sorry albert just checked the schematics and also watterott's HDMI_Display schematic - it's HDMI DDC that the STM32F072 needs to emulate! but looking at the watterott schematics that's just an EEPROM (again).
l.
OK, I'm lost :) and not really familiar with the passthrough card so let me try to find my bearings back; just stop me when I'm wrong. The goal is that the passthrough card advertise on its HDMI connector's I2C the display capabilities of the microdesktop it is slotted into. Correct?
So at the interface level, it should behave as an I2C slave EEPROM wrt DDC_SDA and DDC_SCL (that's I2C1 on the STM32) and as an I2C master wrt the EOM68 connector's I2C. Right?
no, ignore the EOMA68 connector entirely - that has nothing to do with this.
the pins are the ones i listed. which is *NOT* the EOMA68 I2C pins. it's two *SEPARATE* pins which is why it really should be done as bit-banging.
Now, what I am not sure about yet is whether there are any conversion to be made between the I2C data read from the microdesktop(s I2C and the data to be provided on the HDMI DCC IC2.
nnnope! i would have said. it's very very simple. just straight "read EDID data from EEPROM then replay EDID data from EEPROM.".
that's all that's needed.
OK, got it now.
There is no firmware started yet for the passthrough card at git@git.hands.com:eoma-firmware, right ? So I'll start from scratch.
l.
Amicalement,
On Fri, Mar 17, 2017 at 7:42 PM, Albert ARIBAUD albert.aribaud@free.fr wrote:
Bonjour,
Le Fri, 17 Mar 2017 07:23:27 +0000
OK, got it now.
There is no firmware started yet for the passthrough card at git@git.hands.com:eoma-firmware, right ? So I'll start from scratch.
correct - yes please. feel free to make a sibling directory to the laptop one.
l.
Bonjour,
Le Sat, 18 Mar 2017 19:25:07 +0000 Luke Kenneth Casson Leighton lkcl@lkcl.net a écrit:
On Fri, Mar 17, 2017 at 7:42 PM, Albert ARIBAUD albert.aribaud@free.fr wrote:
Bonjour,
Le Fri, 17 Mar 2017 07:23:27 +0000
OK, got it now.
There is no firmware started yet for the passthrough card at git@git.hands.com:eoma-firmware, right ? So I'll start from scratch.
correct - yes please. feel free to make a sibling directory to the laptop one.
l.
OK. I'm currently busy but I'll do it this week-end.
Amicalement,
--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Tue, Mar 21, 2017 at 9:04 PM, Albert ARIBAUD albert.aribaud@free.fr wrote:
correct - yes please. feel free to make a sibling directory to the laptop one.
l.
OK. I'm currently busy but I'll do it this week-end.
no problem there's plenty of time.
arm-netbook@lists.phcomp.co.uk
-
Albert ARIBAUD -
Luke Kenneth Casson Leighton