User`s manual

BL1600
EEPROM s 109
Clock Speed
The clock speed code is used by the BL1600 to compute parameters
necessary to set the serial port. The clock speed is also used by several
Dynamic C library functions.
Changing Parameters Stored in EEPROM
1 Install jumper across pins 1921 on header J1.
2 Use the ee
_
wr function to change the parameters.
3 Reset the BL1600 by interrupting power or by momentarily connecting
pins 910 on header H4.
4 Reconnect pins 1719 on header J1. The BL1600 will automatically
use the new mode or baud rate specified for the next restart. The board
will continue to operate with the new setting until the EEPROM is
changed.
Follow the above procedures to change any of the parameters listed in
Table F-1. First, perform the procedure for one of these parameters, then
repeat the procedure for the other parameters.
Library Routines
The following library routines can be used to read and write the EEPROM.
int ee
_
rd( int address );
int ee
_
wr( int address, char value );
The function ee
_
rd returns the data value in the lower byte, and the
function ee
_
wr writes the character value at address. The functions return
a negative value if there is a hardware problem. If this happens with
ee
_
wr, try writing again after checking pins 1921 on header J1 to make
sure the EEPROM is write-enabled. Repeated negative values may be
indicative of a worn-out EEPROM. A write-protection violation does not
wear out the EEPROM.
These routines each require about 2.5 ms to execute. They are not re-
entrant, that is, only one routine at a time will run.
The EEPROM has a rated lifetime of only 10,000 writes
(unlimited reads). Do not write the EEPROM from within a
loop. The EEPROM should be written to only in response to a
human request for each write.
!