IPC@CHIP Documentation - SC12 @CHIP-RTOS V1.10

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Usage of the TCP/IP API
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1. Processing of a socket callback functions (see Register callback) should be kept at a minimum
to prevent stack overflows.
2. Declaring of socket callback functions with Borland C:
void huge my_callback(int socketdescriptor, int eventflagmask)
3. Declaring of socket callback functions with Microsoft C:
void far _saveregs _loadds my_callback(int sd, int eventmask)
4. The internal TCP/IP stack of the IPC@CHIP allocates memory for buffers smaller than 4096 bytes
from a pre-allocated memory block. Larger buffers are allocated direct from the CHIP-RTOS. If
user TCP/IP network communication sends/receives packets with a size larger than 4096 bytes,
the user application should not use all available memory in the IPC@CHIP because of these
additional allocations. There should be in that case always a minimum of 30-40 KBytes of free
available memory in the IPC@CHIP. The mem command shows the whole memory list of the
IPC@CHIP at runtime. The maximum amount of TCP/IP memory can be configured at chip.ini
(see Set TCP/IP memory size). The application programmer can reduce or increase this size in
chip.ini. With the API call Get TCP/IP memory info it is possible to control the TCP/IP memory
usage at the application runtime.
TCP/IP API
General notes for the usage of the DOS and @CHIP-RTOS int API calls
1. At the start of a user program the Stdio focus should be set to USER. Before ending the
application switch the focus back to SHELL or BOTH (see Set Stdio focus).
2. If more than one user program runs in the IPC@CHIP, only one of them should read characters
from Stdin
3. The functionality of most of the shell commands is also available through calls into the @CHIP-
RTOS INT API. If not, use the @CHIP-RTOS INT call Execute a shell command. This call
executes a shell command from inside the user application.
4. Install a fatal user error handler, which does a reboot of the IPC@CHIP with Install user fatal
error handler
5. Used software interrupts (all others are free for use):
0x00 - Reserved (@CHIP-RTOS Divide Overflow Handler)
0x01 - Reserved (Debugger Trace Interrupt)
0x02 - Reserved (Hardware Non-Maskable Interrupt (NMI))
0x03 - Reserved (Debugger Breakpoint Interrupt)
0x04 - Reserved (@CHIP-RTOS INTO Overflow Handler)
0x05 - Reserved (@CHIP-RTOS Array Bounds Exception Handler)
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