i once thought i had bought a collection of betamax with the hidden episode ;). your SDR video brought me here. as old-electromusik noddler myself very cool! love the AY in a modular format!
is it wise to tie the 3 analogue output directly together? The outputs could be fighting each other, would it be better to use an op-amp to mix them. The data sheet is not very helpful, well not the one i found.
I actually thought the same myself - but there must be internal output resistors on each of the channels taking care of that. Have a look here github.com/nickbild/ay-3-8910/blob/main/docs/AY-3-8910-datasheet.pdf Page 37 has a reference implementation showing the output connection for the 3 channels
No - I am not attempting to read anything from the device. Just setting GPIOs. There are modes where you can read data from the AY-3 - but I didn't attempt to use them
The I2c expander isn't really a good choice for this application. You can buy bidirectional and unidirectional bus transceivers that are powered from two different power rails, in this case 5V and 3V3. Texas makes a lot of these level translator devices. Some examples are the SN74LVC1T45DBVR and the SN74LVC4245APWR to name just a couple.
Thank you for the comment Vince - I was looking for such a device and couldn't find one appropriate. I knew they had to be out there! Ideally I wanted a high speed device with fan out so I didn't have to use up so many pins - do you know if such a device exists?
@@na5yAh, you want to fanout a few pins to many with level translation too ? Serial expansion while trying to fanout is going to always be a latency penalty. You might be able to cobble something together with 595 shift registers and a few pins driven thru a level translator for clocks and enables. Other than that I can't think of anything that comes to mind that'll fit your usecase cleanly.
@@na5y no worries. Take a look at the TI SNx4HC595 device. It has 3 state outputs so you could back to back 2 of them for read, write. you can shift in and enable the output when the word you want to write is fully shifted so the audio device doesn't see partially shifted words.
Very interesting indeed, thanks for the great video and giving me some ideas for what to do over the december holidays :)
Thank you Andre!
i once thought i had bought a collection of betamax with the hidden episode ;). your SDR video brought me here. as old-electromusik noddler myself very cool! love the AY in a modular format!
Thank you - I have a lot of good memories from the "music" these sorts of ICs emitted ;)
is it wise to tie the 3 analogue output directly together? The outputs could be fighting each other, would it be better to use an op-amp to mix them.
The data sheet is not very helpful, well not the one i found.
I actually thought the same myself - but there must be internal output resistors on each of the channels taking care of that. Have a look here
github.com/nickbild/ay-3-8910/blob/main/docs/AY-3-8910-datasheet.pdf
Page 37 has a reference implementation showing the output connection for the 3 channels
that page was not in the datasheet I found on the internet, so looks like you can do it without any issue.@@na5y
I would have thought that you need a level shifter to shift 3V->5V and 5V->3V so you don't damage any of the chips.
No - I am not attempting to read anything from the device. Just setting GPIOs. There are modes where you can read data from the AY-3 - but I didn't attempt to use them
I would add the AY-3 also works fine with the lower level - both on the inputs as well as the input clock
The I2c expander isn't really a good choice for this application. You can buy bidirectional and unidirectional bus transceivers that are powered from two different power rails, in this case 5V and 3V3. Texas makes a lot of these level translator devices. Some examples are the SN74LVC1T45DBVR and the SN74LVC4245APWR to name just a couple.
Thank you for the comment Vince - I was looking for such a device and couldn't find one appropriate. I knew they had to be out there! Ideally I wanted a high speed device with fan out so I didn't have to use up so many pins - do you know if such a device exists?
@@na5yAh, you want to fanout a few pins to many with level translation too ? Serial expansion while trying to fanout is going to always be a latency penalty. You might be able to cobble something together with 595 shift registers and a few pins driven thru a level translator for clocks and enables. Other than that I can't think of anything that comes to mind that'll fit your usecase cleanly.
Thanks again Vince!
@@na5y no worries. Take a look at the TI SNx4HC595 device. It has 3 state outputs so you could back to back 2 of them for read, write. you can shift in and enable the output when the word you want to write is fully shifted so the audio device doesn't see partially shifted words.