FM6124-QG Ramtron, FM6124-QG Datasheet - Page 13

• Manufacturer Part Number: FM6124-QG
• Description: FRAM, 24KB, EVENT DATA REC, QFP44
• Manufacturer: Ramtron

Specifications of FM6124-QG

• Memory Size: 24KB
• Nvram Features: RTC
• Supply Voltage Range: 3V To 3.6V
• Memory Case Style: QFP
• No. Of Pins: 44
• Operating Temperature Range: -40°C To +85°C
• Package / Case: QFP
• Interface: I2C
• Memory: RoHS Compliant
• Interface Type: I2C, Serial, 2-Wire
• Rohs Compliant: Yes
• Access Time: 100 KBPs
• Operating Supply Voltage: 3 V to 3.6 V
• Mounting Style: SMD/SMT
• Lead Free Status / Rohs Status: Details

time a new event is recorded in order to point to the oldest
event.
Write pointer
The Write pointer is used by the Event recorder to indicate
where the next Event will be recorded in the event buffer.
The WP pointer can only move in one direction: up from
the FP address. For this reason the Event storing can be
seen as a stack: more recent events being stored on top of
older ones.
Eventually the WP pointer can roll over the maximum
address. When this situation occurs the FP pointer will be
incremented for each new event recorded. In applications
where the EDR is placed close to the Host processor it is
possible to configure the Event recorder to activate the
INT output for the following situations:
This is done by setting the BF, B75F, B50F bit
respectively in the PINEVENTA register
For situations where the FM6124 is remote from the host
processor, it is always possible for the host processor to
retrieve the number of event present in the event buffer by
reading the Event buffer counter 16-bit register.
Read Pointer
The read pointer RP points to the next event to be read.
This pointer is used to load the next (or previous) event
data into the Event data read back registers (addresses
0x2C
(EDRCMD[3:0] = 0001 is sent to the FM6124.
Contrary to WP, the Read pointer can be configured to
move from older to newer events but also from newer
event toward older ones.
The direction of the RP pointer depends on:
When the READDIR bit is cleared, the RP will fetch event
from FP toward WP. However RP cannot move farther
than WP-1. In situation where FP has reached WP-1 any
attempt to read extra events will make the Event data
recorder to fill the Event data read back registers with
0xFF, set the ERR bit of the Event Data recorder
configuration register and the RP address will not be
incremented.
When the READDIR bit is set and the GET command is
initiated, the RP will fetch the data associated with the next
Rev. 4.0 (EOL)
July 2010
•
•
•
•
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to
Buffer Full
Buffer full at 75%
Buffer full at 50%
The amount of events stored into the Event
memory buffer
The value of the READDIR bit
0x33)
whenever
the
GET
command
events toward FP and place its content into the Event Data
Read back registers. This provided that the RP pointer is
“away” and up from FP address.
In the case where the GET command is sent to the Event
Recorder while the RP = FP, if there is one event recorded
at FP position its content will be placed in the Event Data
register.
However if from that point a second attempt is made to
read Event Data, the Event Data Recorder will fill the
Event data readback registers with 0xFF, set the ERR bit
of the Event Data recorder configuration register and the
RP address will not be incremented (decremented).
Stream Pointer
The stream pointer is a dedicated read pointer that is used
for event reading in stream operations. From a functional
point of view the SP pointer is independent of the RP.
However, like the RP pointer, the direction into which the
SP pointer will mode, depend on configuration of the DIR
bit of the Event Buffer Control register: When the DIR bit
is configured as 0, the SP pointer will mode from oldest
event toward newer event. In the situation where the DIR
bit is set to 1, the SP pointer moves from newer events
towards older ones.
The value of SP is initialized at the moment the STREAM
command (EDRCMD[3:0] = 0011 is initiated.
The SP pointer is used to automatically load the next event
data into the Event data read back registers (addresses
0x2C to 0x33) after the last register (0x33) of the previous
event content is read and the STREAM Event data
recorder command is maintained.
As other pointers, the SP pointer address is not accessible
to the user.
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