Rainbow Electronics AT91CAP9S250A - Manual (Page 256)

256
6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
24.4.4.3 Temperature Compensated Refresh (TCR) or Temperature Compensated Self-refresh (TCSR)
This feature is activated by adjusting Temperature Compensated Refresh bits (TCR) in
BCRAMC Low Power Register (
See “TCR _TCSR: Temperature Compensated Refresh or Tem-
perature Compensated Self-refresh” on page 262. ).
This feature allows to adjust the refresh period in function of different temperatures.
Some Cellular Ram devices include an on chip temperature sensor that automatically adjusts
the refresh period according to operating temperature, in this case the value of TCR is set to 0.
On the contrary, some Cellular Ram devices do not include an internal sensor. In this case,
TCR values can be changed by modifying the TCR bits in the BCRAMC Low Power Register the
Refresh Configuration Register is automatically accessed and TCR value is adjusted before
doing the next access in the Cellular Ram device.
24.4.4.4 Partial Array Refresh (PAR)
This feature is activated by adjusting Partial Array Refresh bits (PAR) in the BCRAMC Low
Power Register (
See “PAR: Partial Array Refresh” on page 262. ).
PAR can restrict the refresh operation to a portion of the total memory area. Data stored in
addresses not receiving refresh will become corrupted.
As soon as TCR field is modified, the Refresh Configuration Register and theTCR bit are auto-
matically updated before doing the next access in the Cellular Ram device.