W925E240 Datasheet, PDF (9/73 Pages) Winbond – 8-BIT CID MICROCONTROLLER

W925E/C240
Power Management
The W925E/C240 has IDLE and POWER DOWN modes of operation. In the IDLE mode, the clock to
the CPU core is stopped however the functions of the timers, divider, CID and interrupts are active
continuously. In the POWER DOWN mode, both of the system clock stop oscillating and the chip
operation is completely stopped. POWER DOWN mode is the state of the lowest power consumption.
6.1 Memory Organization
The W925E/C240 separates the memory into two separate sections, the Program Memory and the
Data Memory. The Program Memory is used to store the instruction op-codes and look-up table data,
while the Data Memory is used to store data or for memory mapped devices.
Program Memory
The Program Memory on the W925E/C240 can be up to 256K bytes that are divided into 4 pages,
each page has the size of 64K bytes. The upper 128K bytes are used to store the op-codes and the
whole 256K can be used to store look-up table data. Because the op-code is 64K addressable, a PG
bit in PAGE register decides which ROM page between page0, page1 is enabled, and the ALU fetches
the op-code from the selected ROM page. If PG=0, ALU fetches the op-code from page0. If PG=1,
ALU fetches the op-code from page1. When MOVC instruction is executed, ALU fetches the look-up
table data according the indication of LT1 and LT0 bits. The value of LT1 and LT0 indicates which
ROM page is active for look-up table instruction.
00000
0FFFF
10000
1FFFF
20000
2FFFF
30000
3FFFF
64K
Page0
64K
Page1
64K
Page2
64K
Page3
PG=0
LT1,0
=00
PG=1
LT1,0
=01
LT1,0
=10
LT1,0
=11
Figure 6-1 Program Memory Map
Publication Release Date: July 12, 2005
-9-
Revision A10