Cytron Technical Forum

Hi everyone! i have tried to use the code given by cytron on this link (http://www.cytron.com.my/p-mod-9001d?keyword=GSM) to send sms. i am using pic16f877a and 4MHz crystal, but i dont succeed to send message, i am using also GSM SIM900. can someone help-me to understand the situation. i have tested the moedem GSM on CCS it worked (so it is not GSM Problem)

Ilidio WROTE:Hi everyone! i have tried to use the code given by cytron on this link (http://www.cytron.com.my/p-mod-9001d?keyword=GSM) to send sms. i am using pic16f877a and 4MHz crystal, but i dont succeed to send message, i am using also GSM SIM900. can someone help-me to understand the situation. i have tested the moedem GSM on CCS it worked (so it is not GSM Problem)

1. I believe the protocol of MOD-001D is not compatible with SIM900.
2. Once the oscillator speed changes, the baudrate changes, you need to change the related register to make it same as using 20MHz, It should be the SPBRG register, but please verify from the datasheet.
3. Since you got the modem working on CCS, just proceed with CCS.