Users Guide: Network Microcontroller Supplement User Manual

High-Speed Microcontroller User’s

Guide: Network Microcontroller

Supplement

210

ADDITIONAL FUNCTIONS AVAILABLE IN ROM VERSION 1.2.0

If the ROM version (as shown when entering the serial loader) is 1.2.0 or greater, the following additional ROM functions are available.

For earlier ROM versions, equivalent functionality is being made available via external C libraries, which can be found at:

http://files.maxim-ic.com/micr

ocontroller/mxtni.

rom_netboot

The rom_netboot function initiates netboot, ignoring the state of the netboot port pin.

task_switcher

This function is the address of the default task scheduler built into the ROM, which is periodically called by the timer interrupt. The

address is exported to make replacement of the timer interrupt handler easier.

tick_calculatereload

This function calculates the reload value for the timer tick based on the CPU crystal speed. The result is saved into directs used by the

timer interrupt handler.

owm_probeclock

This function attempts to determine the processor crystal speed through 1-Wire timing measurements.

Example: If the crystal speed is 18.432MHz, the result is 1843. The result is zero if the bus is shorted, if there is no 1-Wire presence, or

an error occurred during measurement. The result is not very accurate and could be off by as much as +100% to -50%.

owm_calculatedivisor

This function calculates the initialization value for the 1-Wire master given a CPU speed.

info_sendstring

This function prints a zero-terminated string on serial port 0 using bit-bang routines.

info_sendtwohex

This functions prints a hexadecimal value on serial port 0 using bit-bang routines.