Datasheet

28-Pin Demo Board I
2
C™ Demonstration Firmware
© 2009 Microchip Technology Inc. DS51647C-page 139
FIGURE B-2: I
2
C™ WRITE BYTE(S)
Read Byte(s) with Word Address
– The word address is set to begin at a given value
and incremented sequentially during the transaction.
FIGURE B-3: I
2
C™ READ BYTE(S) WITH WORD ADDRESS
Read Byte(s) without Word Address
– The word address will continue in sequence from
the previous transaction to the I
2
C slave. On Reset the device address for all three
slave devices are reset to zero.
FIGURE B-4: I
2
C™ READ BYTE(S) WITHOUT WORD ADDRESS
B.6 SLAVE DEVICES
The 28-Pin Demo Board I
2
C™ demonstration firmware responds to three I
2
C slave
devices: RTC, Serial EEPROM and Executive.
B.6.1 Slave Address: 0xA2 – Real-Time Clock Emulation
The 28-Pin Demo Board I
2
C™ demonstration emulates an I
2
C Real-Time Clock (RTC).
Table B-3 list the word addresses.
DATA
WORD-ADR
SLAVE-ADR
[W]
DATA DATA
AA
A
AS
P
SLAVE-ADR
[R]
A
RS
DATA
WORD-ADR
SLAVE-ADR
[W]
AAS
A
DATA
N
P
DATA
SLAVE-ADR
[R]
DATA
DATAAA
N
SP
TABLE B-3: REAL-TIME CLOCK (RTC) WORD ADDRESSES
REG NAME DESCRIPTION
0x00 RTC_CONFIG_1 7: 0
6: 0
5: STOP – stop time function (0: RUN, 1: STOP)
4: 0
3: 0
2: 0
1: 0
0: 0
0x01 RTC_CONFIG_2 7: 0
6: 0
5: 0
4: 0
3: AF – Alarm flag
2: 0
1: AE – Alarm enable
0: 0
0x02 RTC_SECONDS 00-59 seconds, coding: BCD, bit 7: VL?
0x03 RTC_MINUTES 00-59 minutes, coding: BCD
0x04 RTC_HOURS 00-23 hours, coding: BCD
0x05 RTC_WEEKDAY 00-06 weekday
0x06 RTC_DAYS 01-31 day of the month
0x07 RTC_MONTHS 01-12 month of the year, coding: BCD