MCP795B10 MAS [Micro Analog systems], MCP795B10 Datasheet - Page 15

• Manufacturer Part Number: MCP795B10
• Description: SPI Real-Time Clock Calendar
• Manufacturer: MAS [Micro Analog systems]

REGISTER 5-9:
REGISTER 5-10:
 2011 Microchip Technology Inc.
bit 7
Legend: R = Readable Bit W = Writable Bit U = Unimplemented bit, Read as ‘0’
bit 7
Legend: R = Readable Bit W = Writable Bit U = Unimplemented bit, Read as ‘0’
Note:
Note:
bit 5:4
bit 2:0
bit 7-0
bit 7
bit 6
bit 3
OUT
RW
Bit 7 is the OUT bit, this sets the logic level on the CLKOUT when not using this as a square wave output.
Bit 6 is the SQWE bit, setting this bit enables the divided output from the crystal oscillator.
ALM1 Bits <5:4> determine which alarms are active.
- 00 – No Alarms are active
- 01 – Alarm 0 is active
- 10 – Alarm 1 is active
- 11 – Both Alarms are active
Bit 3 is the EXTOSC enable bit. Setting this bit will allow an external 32.768 kHz signal to drive the RTCC
registers, eliminating the need for an external crystal.
RS2 Bits <2:0> set the internal divider for the 32.768 kHz oscillator to be driven to the CLKOUT. The fol-
lowing frequencies are available. The output is responsive to the Calibration register.
- 000 – 1 Hz
- 001 – 4.096 kHz
- 010 – 8.192 kHz
- 011 – 32.768 kHz
- 1XX enables the Cal Output function. Cal output appears on CLKOUT if SQWE is set (1 Hz nominal).
When RS2 is set to enable the Cal Output function, the RTCC counters will continue to increment.
Calibration Value
This is an 8-bit register that is used to add or subtract clocks from the RTCC counter every minute. The
CALSGN (0x03:7) is the sign bit and indicates if the count should be added or subtracted. The 8 bits in
the Calibration register, with each bit adding or subtracting two clocks, gives the user the ability to add or
subtract up to 510 clocks per minute.
bit 6
SQWE
RW
CONTROL REG 0
CALIBRATION 0
bit 5
ALM1
RW
X
X
09
08
bit 4
ALM0
MCP795WXX/MCP795BXX
RW
Preliminary
CALIBRATION
RW
bit 3
EXTOSC
RW
bit 2
RS2
RW
bit 1
RS1
RW
DS22280A-page 15
bit 0
RS0
RW
bit 0