RX610 Group
25. RAM
R01UH0032EJ0120 Rev.1.20
Page 817 of 1006
Feb 20, 2013
25.
RAM
The RX610 Group has a high-speed static RAM.
25.1
Overview
Table 25.1 lists the specifications of the RAM.
Table 25.1 Specifications of the RAM
Item
Description
RAM capacity
128 Kbytes (RAM0: 64 Kbytes, RAM1: 64 Kbytes)
RAM address
RAM0: 0000 0000h to 0000 FFFFh
RAM1: 0001 0000h to 0001 FFFFh
Access
•
Single-cycle access is possible for both reading and writing.
•
Enabling or disabling of on-chip RAM is selectable.
*
Data retention function
Data in RAM0 can be retained during periods in deep standby mode.
Power-down function
The module stop state is independently selectable for RAM0 and RAM1.
Note:
*
Selectable by the RAME bit in SYSCR1. For details on SYSCR1, see section 3.2.4, System Control Register 1
(SYSCR1).
25.2
Operation
25.2.1
Data Retention
The address space for on-chip RAM is divided into the RAM0 and RAM1 areas. The difference between the two is
whether internal power can be supplied in deep software standby mode.
Whether or not the supply of internal power to RAM0 continues in deep software standby mode is selectable by the
RAMCUTn bit (n = 2 to 0) in DPSBYCR.
If continuation of the supply of internal power is selected, data in RAM0 are retained during periods in deep software
standby mode. The supply of internal power supply to RAM1 is halted at this time, so data are not retained in RAM 1.
See section 8, Low Power Consumption, for details on the DPSBYCR.RAMCUTn (n = 0 to 2) bits.
25.2.2
Power-Down Function
Power consumption can be reduced by setting the module stop control register C (MSTPCRC) to stop supply of the clock
signal to the on-chip RAM.
If the MSTPC0 bit in MSTPCRC is set to 1, supply of the clock signal to RAM0 is stopped. If the MSTPC1 bit in
MSTPCRC is set to 1, supply of the clock signal to RAM1 is stopped.
The respective modules (RAM0 and RAM1) are thus placed in the module stop state by stopping supply of the clock
signals. The initial value after a reset is for the RAM to be operational.
RAM is not accessible if it is in the module stop state. A transition to the module stop state should not be made while
access to RAM is in progress.
For details on the MSTPCRC registers, see section 8, Low Power Consumption.
Summary of Contents for RX600 Series
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