AC164140 Microchip Technology, AC164140 Datasheet - Page 17

• Manufacturer Part Number: AC164140
• Description: MCP79410 RTCC PICtail Plus Daughter Board Memory Kits
• Manufacturer: Microchip Technology
• Series: PICtail™ Plusr

Specifications of AC164140

• Main Purpose: Timing, Real Time Clock (RTC)
• Embedded: -
• Utilized Ic / Part: MCP79410
• Primary Attributes: For Use With Explorer 16, PICDEM PIC18 Explorer, XLP DEV Board, PICkit Serial Analyzer
• Secondary Attributes: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

5.0
The MCP7941X has both on-board EEPROM memory
and Battery-Backed SRAM. The SRAM is arranged as
64 x 8 bytes and is retained when the V
removed, provided the V
enabled. The EEPROM is organized as 128 x 8 bytes.
The EEPROM is nonvolatile memory and does not
require the V
5.1
FIGURE 5-1:
FIGURE 5-2:
The 64 bytes of user SRAM are at location 0x20h and
can be accessed during an RTCC update. Upon POR
the SRAM will be in an undefined state.
Writing to the SRAM and RTCC is accomplished in a
similar way to writing to the EEPROM (as described
later in this document) with the following consider-
ations:
• There is no page. The entire 64 bytes of SRAM or
• The SRAM allows an unlimited number of read/
• The RTCC and SRAM are not accessible when
• The RTCC and SRAM are separate blocks. The
 2011 Microchip Technology Inc.
32 bytes of RTCC register can be written in one
command.
write cycles with no cell wear out.
the device is running on the external V
SRAM array may be accessed during an RTCC
update.
ON BOARD MEMORY
SRAM
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
BAT
supply for retention.
SRAM/RTCC BYTE WRITE
SRAM/RTCC MULTIPLE BYTE WRITE
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
BAT
S
T
A
R
T
S 1 1 0 1
supply is present and
CONTROL
BYTE
1 1 1
BAT
S 1 1 0 1
S
T
A
R
T
CC
0
.
supply is
A
C
K
CONTROL
x
BYTE
ADDRESS
Preliminary
1 1 1
BYTE
0
A
C
K
x
ADDRESS
A
C
K
• Read and write access is limited to either the
• Data written to the RTCC and SRAM are on a per
BYTE
RTCC register block or the SRAM array. The
Address Pointer will rollover to the start of the
addressed block.
byte basis.
Note:
DATA BYTE 0
Entering an address past 5F for an SRAM
operation will result in the MCP7941X not
acknowledging the address.
A
C
K
A
C
K
DATA
DATA BYTE N
MCP7941X
A
C
K
S
T
O
P
P
DS22266B-page 17
A
C
K
S
T
O
P
P