No NRST pin, How to program STM8S001J3M with SWIM interface,

[XLi.3]

Hi,

I want to program STM8S001J3M with SWIM interface, and the device doesn't have NRST pin,

I see in the datasheet there is :

Only the “connect on-the-fly�? method can be used to program the device through the SWIM interface. The “connect under-reset�? method cannot be used because the NRST pin is not available on this device.

We have supported some device,  STM8S003,STM8S005, which have NRST pin.

I would like to ask what the difference between the  “connect on-the-fly�? method and “connect under-reset�? method, is there document on how to program  “connect on-the-fly�? method?

Thanks very much!

Shirley

[Cristian Gyorgy]

Hi Shirley,

"connect on-the-fly" means that SWIM interface has to be active - so, you cannot use the SWIM pin for other tasks. When SWIM is active, the programmer can connect to the SWIM interface without the need to reset the µC. Of course, this means you would lose one precious pin out of the 6 available, so this is why in the manuals the programming start delay is recommended before you disable SWIM and start using the pin for it's job.

"connect undr-reset" means that whatever you are using the SWIM pin for, the programmer will pull reset down, and under reset SWIM is always active. In this case you don't have to worry about disabling SWIM from within the code.

So, you don't need the NRST pin, just connect SWIM, Vdd, GND, and progrmaing will work if you did not disable the SWIM interface.

[XLi.3]

​Hi Cristian,

Thank you very much, The explanation is very clear.

I would like to ask one more question, does the STVP support to program STM8S001J3M? I use the ST link to program the device, but  it always connect failed.

Thanks!