User`s manual

PK220050 s Software Reference
Software Drivers
Drivers are functions that simplify accessing PK2200 hardware and I/O.
For the following reasons, Z-World drivers make writing software easier:
 Provide commonly needed functionality.
 Eliminate the need to know all of the details of operation.
 Previously tested.
 Simplify source code by replacing multiple lines of code with one
function call.
Refer to the Dynamic C Technical Reference Manual for
more information on using drivers.
Real Time Clock (RTC)
The RTC keeps the date and the time of day with a resolution of one
second. The worst case error is 50ppm (4.3 seconds) per day. Leap years
and variances in the number of days in a month are automatically tracked.
The following structure holds the time and date:
struct tm {
char tm
_
sec; // 0-59
char tm
_
min; // 0-59
char tm
_
hour; // 0-23
char tm
_
mday; // 1-31
char tm
_
mon; // 1-12
char tm
_
year; // 0-150 (1900-2050)
char tm
_
wday; // 0-6 where 0 means Sunday
};
The following routines read and write to the real-time clock:
 int tm
_
wr( struct tm *x )
Sets the system time to the values in the structure pointed to by *x.
PARAMETER1: Pointer to the structure holding the system time
information to be written.
RETURN VALUE: 0 if successful; -1 if clock failing or not installed.
 int tm
_
rd( struct tm *t )
Reads the current system time into the structure t.
PARAMETER1: Pointer to the structure used to store the system time.
RETURN VALUE: 0 if successful; -1 if clock failing or not installed.
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