SM5100B wiring

I’m working with the SM5100B GSM/GPRS module and I have some questions. The datasheet is pretty awful: http://www.sparkfun.com/datasheets/Cell … Manual.pdf

Page 24: How would I wire the battery charging interface? What’s shown on the datasheet doesn’t make any sense to me.

Page 22: Is the reset pin pulled high internally or not? How should I wire the reset pin (active low) to be controllable from an atmega?

Page 19: The UART is described to be used only by “ARM.” I assume that means arm processors, though I don’t know why that would be. Do I have to use the flow control lines on UART0? I’m only sending AT commands and getting replies from the module

Thanks. I hope i can get this figured out soon, i’m in a little bit of a time crunch :slight_smile:

I suppose they mention ARM because that is what most mobile phones use, and one of the ARM UARTs usually has all the modem control signals. The two wire interface should work OK. It looks like you need to hold the Reset pin high, and pulse it low for 100 us if you want a reset. It has a power on reset. The manual is very badly written.

I’d forget it and get something with proper documentation like a Telit module.

Unfortunately cost is a big issue here and the $30 saved by using the SM5100B over the GM862 is important.

Any ideas about the charge interface or the reset pin?

Hey guys, Just working on getting this module going as well. What are you integrating it into and have you started your 2 wire uart0 code yet?