R01UH0823EJ0100 Rev.1.00
Page 1658 of 1823
Jul 31, 2019
RX23W Group
49. RAM
49.
RAM
This MCU has an on-chip high-speed static RAM.
49.1
Overview
lists the specifications of the RAM.
Note 1. Selectable by the RAME bit in SYSCR1. For details on SYSCR1, see section 3.2.2, System Control Register 1 (SYSCR1).
49.2
Operation
49.2.1
Low Power Consumption Function
Power consumption can be reduced by setting module stop control register C (MSTPCRC) to stop supply of the clock
signal to the RAM.
Setting the MSTPCRC.MSTPC0 bit to 1 stops supply of the clock signal to RAM.
Stopping supply of the clock signal places the RAM in the module stop state. The RAM operates after initialization by a
reset.
The RAM is not accessible in the module stop state. Do not allow transitions to the module stop state while access to
RAM is in progress.
For details on the MSTPCRC register, see
section 11, Low Power Consumption
49.2.2
Notes on Self-Diagnosis of the RAM
A write buffer is mounted for the RAM. When the same address is read after a write operation, data in the write buffer,
rather than in the memory cell of the RAM may be read. When the RAM is self-diagnosed, confirm that the data have
been written by following the procedure below so that data will not be read from the write buffer.
(1) Write data to the address targeted for diagnosis.
(2) Write data to an address which is at least 4 addresses away from the that in (1).
(3) Read the data from the address in (1).
Table 49.1
Specifications of RAM
Item
Description
Capacity
64 Kbytes (0000 0000h to 0000 FFFFh)
Access
Single-cycle access is possible for both reading and writing.
On-chip RAM can be enabled or disabled.*
Low power consumption function
Transitions to the module stopped state are possible.