3 MEMORY MAP
3-4
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
Area 6 (I/O Area)
3.5
Area 6 is allocated to the I/O area for the internal peripheral circuits.
For details on the internal peripheral circuits mapped to this area, see the descriptions of each peripheral module.
For the list of control registers, see the “List of I/O Registers” section in Appendix.
Area 6 includes BBRAM (16 bytes) located at addresses 0x300b00 to 0x300b0f. BBRAM operates with a power
source (RTCV
DD
) separated from the system power. Thus, BBRAM can retain data even if the system power is off.
External Memory Area
3.6
Areas 4, 5, 7 to 10, 13 to 16, and 19 to 22 can be used for external memory and other external devices. Configure
the SRAMC and/or SDRAMC according to the devices connected. Although the internal address and internal data
buses of the S1C33L26 are both 32 bits wide, the maximum external data bus width is 16 bits (D[15:0]) and the
maximum external address bus width is 26 bits (A[25:0]) due to the limited number of pins available.
Notes: • A NAND Flash can be connected to Area 9 (4M bytes) or Area 22 (2G bytes).
• An SDRAM can be connected to Area 7 (2M bytes) or Area 19 (256M bytes).
• The external VRAM used for the graphics engine and LCD controller can be connected to Ar-
eas 4 to 22.
Bus Masters and Accessible Memories
3.7
The table below lists the bus masters and the memories that can be accessed.
7.1 Bus Masters and Accessible Memories
Table 3.
Memory
Bus master
CPU
DMAC
LCDC
GE
IRAM (Area 0)
3
–
–
–
IVRAM (Area 0)
3
–
–
–
IVRAM (Area 3)
3
3
3
3
DSTRAM (Area 3)
3
3
–
–
LUTRAM (LCDC module)
–
–
3
–
I/O registers (Area 6)
3
3
–
*
External memory
3
3
3
3
3
: Can be accessed. –: Cannot be accessed.
*
: The GE can only write data to the USIL transmit data buffer via the BLKCOPY command.
Memory Access Rate
3.8
(1) Internal RAM and external SRAM access rate
8.1 Static Memory Access Cycle
Table 3.
Memory access cycle
Number of access cycles
Single byte
Single half-word
Single word
Successive
address
Burst
access
IRAM (12KB/Area 0) read
2
2
2
1
–
IRAM (12KB/Area 0) write
1
1
1
–
–
IRAM (20KB/Area 0) read
2 + W
2 + W
2 + W
1 or 1 + W (
*
1)
–
IRAM (20KB/Area 0) write
1
1
1
–
–
Cache RAM read
2
2
2
–
–
Cache RAM write
1
1
1
–
–
DSTRAM (512B/Area 3) read
4
4
4
–
–
DSTRAM (512B/Area 3) write
4
4
4
–
–
IVRAM (20KB/Area 3) read
4 + W
4 + W
4 + W
–
1 + W (
*
2)
IVRAM (20KB/Area 3) write
4
4
4
–
–