The zx40N based project will only start when the USB lead is plugged in.
The USB adapter is permanently wired to the ZX40. Is there a recommended way to tie RST to prevent this behaviour or will I have to disc RST when not loading ?
Correct way to pull up/down RST
Re: Correct way to pull up/down RST
I'm not sure that I fully understand the issue but I gather that when the USB cable is not connected to the USB adapter the reset line is being pulled low somehow by the USB adapter.FFMan wrote:Is there a recommended way to tie RST to prevent this behaviour [...]?
It may be beneficial to connect the reset signal from the USB adapter to the reset line of the ZX-40n through a diode (anode to the ZX reset, cathode to the USB reset). Although the AVR devices have an internal pull up on the reset input, it still may be advisable to employ an external pull up, perhaps 10K or so.
- Don Kinzer