LPCXpresso1769 With SIM908 Module

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by Natalia_Requejo on Sat Jul 12 09:43:11 MST 2014
Hi, I'm developing a GPS/GPRS tracker, for this project I'm using a GSM / GPRS / GPS module the SIM908,
In my design I use a voltage of 4.6 V in EXT_PWD to feed the LPCXpresso 1769.

The LPCXpresso works perfectly, but after using it several times communicating with SIM908 (using UART1 and UART2) the SIM908 stopped working.
I think the SIM908 TX or RX  have been burned.

My question is, what level of output voltage using LPCXPRESSO UART1 and UART2 in?

The SIM908 specification said
Digital interface characteristics

high level input voltage min 2,4V
low level input voltage  max 0,4V

high level output voltage min 2,7V
low level output voltage max 0.1V

So I think i burn SIM908