Do I have to control the SS lines to Ethernet and SD Card when using both?

Projects Networking, Protocols, and Devices
1

Hi

My equipment:
Arduino MEGA 2560 R3, Arduino Ethernet shield R3 with Micro SD Card,
Homemade shield with DS1307 RTC and interface to LCD (2x40)
Developement environment:
Win XP S3, Arduino 1.0.5

I have a script doing the following:
In setup:
Pre setup of Ethernet (MAC, IP,etc) and SD Card (selectPin).
A file on the SD Card contains MAC Addresses on up to 10 DS18B20 Thermo sensors.
This file is read and stored in a table in memory.
A logfile on the SD Card are opened with Date (YYYYMMDD) as filename.
In loop:
Temperatures are read from all DS18B20 and displayed via Serial.print and on the LCD.
All sensors current temperature, max.temp and min.temp are shown on a web page.
Every 5'th min. the time and current temperatures are stored in csv format into the logfile.
At midnight the logfile are closed, and a new opened with a new filename.

So far everything works fine, but intermittent everything hangs up - nothing happens.
Sometimes a new access to the web page will start the whole process again, but most of
the time, a reset must be done.

My question is: Must I control the shift of the SS pins for the Ethernet and the SD Card,
when needed, or is it done automatically by Ethernet.h, SPI.h and SD.h ?

2

My question is: Must I control the shift of the SS pins for the Ethernet and the SD Card,when needed, or is it done automatically by Ethernet.h, SPI.h and SD.h ?

Once both devices are initialized, the libraries control those SS pins.

You should post your code and explain where the sketch hangs up.