CY82C693UB Cypress Semiconductor Corporation., CY82C693UB Datasheet - Page 101

• Manufacturer Part Number: CY82C693UB
• Description: Hypercache Tm / Stand-alone Pci Peripheral Controller With Usb
• Manufacturer: Cypress Semiconductor Corporation.

CY82C693UB Real-Time-Clock Registers
The RTC inside the CY82C693UB contains a time-of-day
clock, an interrupt generating alarm, a 100 year calendar, a
software controlled periodic interrupt, and 242 bytes of bat-
tery-backable static RAM (for scratch data). An external bat-
tery and a 6 pF or a 12 pF 32.768-kHz crystal in parallel with
a 6-pF capacitor are all that must be provided to enable the
RTC to keep time in battery-backed mode. Leap-year and day-
light savings time will be automatically adjusted.
RTC registers are accessed using I/O addresses 070H and
071H. The index address of the register must first be placed in
the RTC’s Index Address Register. This is loaded through an
I/O write to address 070H with the register index as the write
data. Following the I/O write to 070H, an I/O access (read or
PLEASE NOTE: Where the registers are called out BCD (binary coded decimal), the values must be written/read as BCD
values (Not Hexadecimal).
RTC Register 0: Seconds Byte (Read/Write except for bit 7 which is always 0)
RTC Register 1: Seconds Alarm (Read/Write)
RTC Register 2: Minutes Byte (Read/Write)
RTC Register 3: Minutes Alarm (Read/Write)
RTC Register 4: Hours Byte (Read/Write)
RTC Register 5: Hours Alarm (Read/Write)
RTC Register 6: Day-of-the-Week Byte (Read/Write)
Bit
7:0
Bit
7:0
Bit
7:0
Bit
7:0
Bit
7:0
Bit
7:0
Bit
7:0
Function
BCD representation of seconds (must be in the range 00–59)
Function
BCD representation of seconds alarm (must be in the range 00–59)
If bit 7:6=11, then a 1 second periodic interrupt will occur.
Function
BCD representation of minutes (must be in the range 00–59)
Function
BCD representation of minutes alarm (must be in the range 00–59)
Function
BCD representation of hours
12-hour Mode:
24-hour Mode:
Function
BCD representation of hours alarm
12-hour Mode:
24-hour Mode:
Function
BCD representation of day-of-the-week (must be in the range 01–07); 01=Sunday.
Must be in the range 01–12 (AM) or 81–92 (PM)
Must be in the range 00–23
Must be in the range 01–12 (AM) or 81–92 (PM)
Must be in the range 00–23
PRELIMINARY
Index=04H
Index=05H
Index=02H
Index=03H
Index=01H
Index=06H
101
write) to address 071H will read or write the contents of the
appropriate RTC register.
The scratch data is broken into two separate blocks. Access to
the blocks is controlled through I/O accesses to different ad-
dresses. The lower 128 register bytes (this includes the Clock
Data) are accessed using I/O writes to address 070H (with
register index as the write data) followed by I/O reads or writes
to address 071H. The data for the I/O access to 071H is the
contents of the desired register. For the upper 128 scratch
RAM bytes, the scratch RAM address should be written to I/O
address 072H followed by a data read or write to I/O address
073H.
Index=00H
CY82C693UB
Default
00000000
Default
00000000
Default
00000000
Default
00000000
Default
00000000
Default
00000000
Default
00000000